Outside the high school program / Sequence and spreadsheet (old 1L) 16 exercises (including 3 corrected)

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123456789ABCDERaisondelasuitearithmétiqueTempsnécoulé(endixièmedeseconde)Abscissexndelaballe(enmètre)Ordonnéeyndelaballe(enmètre)002,512,82,421625,62,186431,794441,24565140,54 x0yij 1. Sequences, statistics and spreadsheets E.202 In this exercise, all times are ex-pressed in tenths of a second and distances in meters. The trajectory of a tennis ball is modeled by a curve in a reference frame O ; i ; j , shown in the graph below. One unit represents one meter. The tennis player hits his ball at time 0 in M 0 coordinates (0 ; 2.5) . For an integer n , the position of the player’s ball in the O ; i ; j at time n is point M of coordinates ( x n ; y n ) . Val-ues x n and y n for n between 0 and 5 are given by the table in the appendix, extracted from a spreadsheet. This table must be completed during the exercise and returned with the copy. Questions 1 to 4 are to a large extent independent 1 Study of the sequence of numbers x n (abscissas of the ball’s position at time n ) a Show that the values x 0 , x 1 and x 2 are the first terms of an arithmetic sequence whose reason r will be de-termined. Write the found value of r in cell E11 of the table in the appendix. b Assume that the numbers x n are the terms of the arith-metic sequence with first term x 0 and reason r . Justify that x n =2.8 n . c We want to introduce into cell B7 a formula recopied to B9 , still valid if we change the value of r . Give this formula. d Complete the two missing cells in column B of the table in the appendix. e The ball arrives at the net, located 12 meters from point O , at time t . Using the spreadsheet, give a frame for t between two values a tenth of a second apart. 2 Study of the sequence of numbers y n (ordinates of the ball’s position at time n ) a Show that the sequence of numbers y n is neither arith-metic nor geometric. b The laws of physics allow us to establish the relation-ship : y n = 0.0784 · n 2 + 2.5 Which table formula should be written in C4 so that it can be copied to C9 ? 3 Study the trajectory of the ball. The net, located 12 meters from the point O measures ap-proximately 0.90 m in height. Explain, using the graph recalled in the appendix, why the ball passes over the net. 4 When the ball is put into play, the serving player is al-lowed two attempts to place the ball in the opponent’s service box. These attempts are called first and second serves. In the course of a match, the player has missed 20 first serves. He has therefore played 20 second serves. a In this match, of the 20 second serves, 3 were successful without being caught by the opponent. Of the second serves, what percentage were successful without being caught by the opponent? b Of these 20 second serves, 65 % were placed in the opponent’s service box. Calculate the number of suc-cessful second serves. c The 20 missed first serves correspond, for the first serves played, to a failure percentage of 26.7 % (rounded to 0.1 % ) . What is the total number of first serves the player performed in this match? values of x n and y n Graphique https://chingmath.fr sacados/202 123456789ABCDERaisondelasuitearithmétiqueTempsnécoulé(endixièmedeseconde)Abscissexndelaballe(enmètre)Ordonnéeyndelaballe(enmètre)002,512,82,421625,62,186431,794441,24565140,54 x0yij
1234567891011121314151617ABCDEFMontantdesmensualitésdeJules160Tauxd’augmentationdesmensualitésdeLéo3%SommetotalerembourséeparJulesMontantdesmensualitésdeLéoSommeinitialeversée801251ermois2emois3emois5601374emois7201415emois8801456emois10401497emois12001548emois13601589emois152016310emois168016811emois184017312emois2000Sommetotaleremboursée20002000 E.1884 Jules and Léo decide to buy the same laptop. They don’t have enough money to pay immedi-ately. The seller offers them easy payment terms. Including interest, each will have to pay a deposit and repay a total of 2.000 euros (including deposit) over 12 months according to terms to be defined. Jules chooses to pay 80 euros at the time of purchase, then repays fixed monthly installments of 160 euros each of the following 12 months. Léo pays 125 euros up front, then his monthly payments in-crease by 3 % each of the following 11 months. So his first monthly payment will increase by 3 % compared with the 125 euros initially paid. On 12 e month, he repays the difference between the 2000 euros owed and the total sum he has already repaid. Part I : Jules ’s choice Let’s note u 0 the sum paid by Jules when buying the com-puter, and u n the total sum repaid by Jules after n months. Thus, u 0 =80 and u 1 represents the total amount Jules has repaid at the end of the first month. 1 Calculate u 1 and u 2 . 2 a What is the nature of the sequence ( u n ) ? Justify. b Express u n in terms of n . 3 To calculate how much Jules has repaid each month, we use a spreadsheet. The spreadsheet is given in Appendix 1. What formula can be entered in cell 5 , so that it can be copied down to B16 ? Part II : Leo’s choice We note v 0 the sum paid by Léo to purchase the computer, and v n the amount of Leo’s monthly payment on n ième month with n integer between 1 and 11. Thus, v 0 =125 and according to the terms of the contract, v 1 =129 rounded to the nearest euro. 1 Calculate v 2 . Round to the nearest euro. 2 What is the nature of the sequence ( v n ) ? Justify. 3 To calculate Leo’s monthly payments, we also use the spreadsheet given in Appendix 1. What formula can be entered in cell E5 , so that it can be copied down to E15 ? Answers provided have been rounded to the nearest whole number. 4 a What total sum has Leo repaid at the end of 11 e month. What is the 12 e monthly payment? b What formula can be entered in cell E16 to directly calculate this 12 e monthly payment? 5 Starting in which month are Leo’s monthly payments higher than Jules’? E.176 asia June 2006 8 points The following article was taken from a weekly newspaper: ˇ At the height of the Trente Glorieuses, when purchasing power grew by 4.2 % per year, it took only sixteen years for an employee to double his net salary (in constant francs) . At the same time, the purchasing power of an executive was equiva-lent to just over twice that of an employee. In short, looking at the easy life of an executive family, an employee house-hold, had before its eyes its future consumption level. Aboard his Dauphine, he could dream of the Peugeot 104! In the ’80s, this growth rate rose to 2 % on average, raising hopes of a catch-up over more than one generation. To my son, the R 16 . . . in thirty-five years! Between 1990 and 2000, this rate plunged to 0.7 % . From now on, a century will barely suffice to achieve such a result. The Megane for the great-grandson. . . Not very moti-vating. ı The aim of this exercise is to examine the accuracy of the three durations announced in this text using a variety of ap-proaches. Part A - Using a graph This part looks at the following extract from the article: ˇ When purchasing power grew by 4.2 % per year, it took an employee just sixteen years to double his or her salary. ı In the Trente Glorieuses, a year noted 0 is taken as the refer-ence year. The graph below shows the rate of increase in purchasing power as a function of the number of years elapsed. For ex-ample, after eight years, purchasing power has increased by 40 % . https://chingmath.fr sacados/1884 1234567891011121314151617ABCDEFMontantdesmensualitésdeJules160Tauxd’augmentationdesmensualitésdeLéo3%SommetotalerembourséeparJulesMontantdesmensualitésdeLéoSommeinitialeversée801251ermois2emois3emois5601374emois7201415emois8801456emois10401497emois12001548emois13601589emois152016310emois168016811emois184017312emois2000Sommetotaleremboursée20002000 sacados/176 Asie - juin 2006 - 8 points
0123456789101112131415161718192012345678910111213 222324252627282930313233343536373839404142ABAnnéeCoe`cientmultiplicateur11,02021,04031,06141,08251,10461,12671,14981,17291,195101,219111,243121,268131,294141,319151,346161,373171,400181,428191,457201,486 2223242526272829303132333435363738394041AB211,516221,546231,577241,608251,641261,673271,707281,741291,776301,811311,848321,885331,922341,961352,000362,040372,081382,122392,165402,208 Jours01234567Concentration de radon020040060080010001200Deecroissanceradioactive 1 Is the growth in purchasing power linear? Justify. 2 is the sixteen-year duration announced above correct? Part B In this part we are interested in the following extract from the article: ˇ In the 1980s, this growth rate rises to 2% on average, giving hope of catching up over more than one generation. To my son, the R16. . . in thirty-five ans ı. We propose to study the evolution of purchasing power from the year 1980, taken as the initial year and which will be noted 0. The table below shows the multiplier coefficients, rounded to the thousandth, that must be applied to the purchasing power of year 0 to obtain the purchasing power after n years. The values in the column B have been rounded to the thou-sandth. 1 Justify the contents of cell B2 . 2 The formula in cell B3 has been copied down. What is this formula? 3 Is the journalist’s sentence recalled at the beginning of this part correct? Part C - Using a sequence In this part, we’re interested in the following extract from the article: Between 1990 and 2000, this rate plunges to 0.7% . From now on, a century will barely suffice to achieve such a result. We note C 1 the multiplier coefficient that must be applied to the purchasing power of the year 1990 to obtain that of the year 1991. Similarly, we define C 2 the multiplier coefficient that must be applied to the purchasing power of the year 1990 to obtain that of the year 1992, C 3 the multiplier coefficient that must be applied to the purchasing power of the year to obtain that of 1993, . . . , C n the multiplier coefficient that must be ap-plied to the purchasing power of the year 1990 to obtain that of the year 1990+ n . 1 What is the nature of the sequence ( C n ) thus con-structed? Specify its first term and its reason. 2 Using your calculator, deduce whether the duration of one century given above is correct. The procedure will be explained. E.185 The main source of natural radioac-tivity to which humans are exposed is a radioactive gas called radon. It escapes from volcanic and granite subsoils, as well as from certain building materials, and stagnates in poorly ventilated areas. Indoor radon concentration is expressed in Becquerels per cu-bic meter ( Bq · m 3 ) . Part A In an experiment, the radon concentration was read at the end of each day. The graph below shows the readings for one week. For example, at the end of the second day, the radon concen-tration is approximately 1 000 Bq · m 3 1 Using graphical representation : a Explain why, in this situation, the decay is not linear. b Determine the day on which the radon concentration becomes less than half of the first day. 2 The following table shows the numerical data measured during the experiment. In one table, data concerning radon gas concentration were entered. The multiplication coefficient between two consecutive values was calculated. https://chingmath.fr 0123456789101112131415161718192012345678910111213 222324252627282930313233343536373839404142ABAnnéeCoe`cientmultiplicateur11,02021,04031,06141,08251,10461,12671,14981,17291,195101,219111,243121,268131,294141,319151,346161,373171,400181,428191,457201,486 2223242526272829303132333435363738394041AB211,516221,546231,577241,608251,641261,673271,707281,741291,776301,811311,848321,885331,922341,961352,000362,040372,081382,122392,165402,208 sacados/185 Asie - Juin 2004 - 11 points Jours01234567Concentration de radon020040060080010001200Deecroissanceradioactive
12ABCDEFGHIn0123456un408 Jour Concentration de radon (en Bq · m 3 ) Coefficient multiplicateur 1 1200 2 996 0.83 3 840 0.84 4 696 0.83 5 576 0.83 6 480 0.83 7 408 0.85 a What is the percentage change in radon concentration between day 1 and day 2? b The numerical data allow us to choose an exponential decay model. Justify this choice. c What is the percentage decrease in radon concentra-tion during the first week? Part B 1 From day 7, it is assumed that decay continues with 0.84 as the value of the multiplier coefficient. a What would be the radon concentration on day 8? Round to the nearest integer. b We model this decay by a sequence ( u n ) where u n rep-resents the radon concentration on day n +7 . We then have u 0 =408 . What type of sequence is this? Justify that : u n =408 × (0.84) n . 2 The table below is extracted from a spreadsheet : Columns are marked with the letters A , B , C ,. . . and the rows are marked with numbers 1 , 2 , 3 . . . We want to write in cell C2 a formula that will allow us to obtain by recopying to the right the terms of the sequence up to u 6 . a Among the following formulas, copy celle (s) that fits (or fits) : =$B$2 × 0.84 =408 × (0.84)^C1 =408 × 0.84 =B2 × (0.84)^C1 b Suggest a formula to be entered in C2 in such a way that it remains valid if the value of cell B2 is changed. c Complete the table in Appendix (to be returned with the copy) using a calculator (results will be rounded to the nearest integer) . 3 The Conseil Supérieur d’Hygiène Publique has issued an opinion on the harmfulness of this gas in dwellings: be-low 200 Bq · m 3 , it is considered harmless. Determine the day from which the radon concentration is less than 200 Bq · m 3 E.183 For all calculations in this exercise, we will round up to the euro cent Pierre, a new graduate, has two job offers from two differ-ent companies. Before accepting either offer, he studies the salaries offered by each company. Partie A Entreprise Boss The Boss company offers him the following contract for em-ployment starting 1 er January 2005: the initial monthly salary is 1 180 e and increases each 1 er January by 12 e . We note u 0 this initial salary, u 1 the salary at 1 er January 2006, u 2 the salary at 1 er January 2007. . . , u n the salary at 1 er January of the year (2005+ n ) . 1 Calculate u 1 and u 2 . 2 What is the nature of the sequence ( u n ) ? Justify your answer. 3 a Express u n as a function of n for any natural number n . b What would his monthly salary be in 2010? Company Rapido The Rapido company offers him, for the same job starting 1 er January 2005, the following employment contract : the initial monthly salary is 1027.50 e and increases each 1 er January by 3.5% . We note v 0 this initial salary, v 1 the salary at 1 er January 2006, v 2 the salary at 1 er January 2007,. . . , v n the salary at 1 er January of the year (2005+ n ) . 4 Calculate v 1 and v 2 . 5 What is the nature of the sequence ( v n ) ? Justify your answer. 6 a Express v n as a function of n for any natural number n . b What would his monthly salary be in 2010? Part B Before making his choice for one or other of the companies, Pierre wants to compare the successive amounts of the salaries proposed. To do this, he creates a table using a spreadsheet program 1 Explain how Pierre was able to complete the column A (cells going from A2 to A14 ) without having to type all the values contained in these cells. 2 What formulas must he write in cells B2 and B3 to obtain, by copying it down, the terms of the sequence ( u n ) in the column B ? 3 What formulas must he write in cells E2 and E3 to obtain, by copying it down, the terms of the sequence ( v n ) in the column E ? 4 Table 2 records the results obtained. Complete all the empty cells in this table in the appendix to be returned with the copy Part C 1 Compare the evolution of monthly wages in each com-pany. 2 a In which year, for the first time, will the Rapido com- https://chingmath.fr 12ABCDEFGHIn0123456un408 sacados/183
1234567891011121314ABCDEFGAnnéeSalairemensuelavecBossSalaireannuelavecBossCumuldessalairesavecBossSalairemensuelavecRapidoSalaireannuelavecRapidoCumuldessalairesavecRapido2005200620072008200920102011201220132014201520162017 1234567891011121314ABCDEFGAnnéeSalairemensuelavecBossSalaireannuelavecBossCumuldessalairesavecBossSalairemensuelavecRapidoSalaireannuelavecRapidoCumuldessalairesavecRapido20052006200720082009201020112012201320142015201620171180,0014160,0014160,001027,5012330,0012330,001192,0014301,0028464,001063,4612761,5525091,551204,0014448,0042912,001100,6813208,2038299,751216,0014592,0057504,001139,2113670,4951970,251228,0014736,0072240,001179,0812330,0066119,201240,0014880,0087120,001220,3514644,1780763,381252,0015024,00102144,001263,0615156,7295920,091264,0015168,00117312,001307,2715687,20111607,201276,0015312,00132624,001353,0216236,26127843,551288,0015456,00148080,001400,3816804,52144648,081300,0015600,00163680,001449,3917392,68162040,761312,0015744,00179424,001500,1218001,43180042,191324,0015888,00195312,001552,6218631,48198673,66 pany’s cumulative earnings exceed the Boss company’s cumulative earnings? b Compare with the results obtained in question C 1 and comment. Table 1. Monthly wages and cumulative wages Table 2. Affichage monthly salaries and cumulative des salaries E.181 The following table gives the number of Internet users worldwide (in millions) for the years 1995 to 2000. Année 1995 1996 1997 1998 1999 2000 Nombre d’utilisateurs (en millions) 34 56 92 145 243 414 We want to use a spreadsheet to analyze this data. The table provided in annex (to be returned with the copy) has been drawn up Part A 1 Explain how it is possible to complete the column A with-out having to enter all the values contained in the cells. 2 In cell C3 , we have calculated the quotient of the number of Internet users in 1996 by the number of Internet users in 1995. What does this quotient represent? What formula should be entered in cell C3 to perform this calculation and obtain the numbers in column C ? 3 a What is the percentage increase in the number of Internet users between 1995 and 1996? Between 1996 and 1997? (Percentages rounded to the nearest whole number will be given.) b What formula must be entered in cell D3 to obtain, by copying down, the percentages of variation in the number of Internet users over the years? c Complete column D of table in appendix (to be returned with copy) d Is the growth in the number of Internet users between 1995 and 2000 exponential? Justify your answer. Partie B 1 To study the growth in the number of Internet users worldwide, we choose to model it by a geometric sequence ( u n ) of first term u 0 =34 . The task is to find a value for the reason of this geometric sequence, which allows this modeling. This value will be entered in the cell I1 . What formula should be entered in cell F3 to calculate u 1 , using the contents of cell I1 , so as to obtain, by copying down, the terms u 2 , u 3 , u 4 and u 5 ? In this way, values can be automatically updated if the number contained in cell I1 is changed. In the rest of the exercise, we will take 1.645 as the value of the reason for the sequence ( u n ) . 2 Calculate u 1 , u 2 , u 3 , u 4 and u 5 , then complete the col-umn F of the table in the appendix to be returned with the copy (results rounded to the nearest unit will be given) 3 Assuming that, until 2004, this model remains reliable, give an estimate of the number of Internet users world-wide in 2004. https://chingmath.fr 1234567891011121314ABCDEFGAnnéeSalairemensuelavecBossSalaireannuelavecBossCumuldessalairesavecBossSalairemensuelavecRapidoSalaireannuelavecRapidoCumuldessalairesavecRapido2005200620072008200920102011201220132014201520162017 1234567891011121314ABCDEFGAnnéeSalairemensuelavecBossSalaireannuelavecBossCumuldessalairesavecBossSalairemensuelavecRapidoSalaireannuelavecRapidoCumuldessalairesavecRapido20052006200720082009201020112012201320142015201620171180,0014160,0014160,001027,5012330,0012330,001192,0014301,0028464,001063,4612761,5525091,551204,0014448,0042912,001100,6813208,2038299,751216,0014592,0057504,001139,2113670,4951970,251228,0014736,0072240,001179,0812330,0066119,201240,0014880,0087120,001220,3514644,1780763,381252,0015024,00102144,001263,0615156,7295920,091264,0015168,00117312,001307,2715687,20111607,201276,0015312,00132624,001353,0216236,26127843,551288,0015456,00148080,001400,3816804,52144648,081300,0015600,00163680,001449,3917392,68162040,761312,0015744,00179424,001500,1218001,43180042,191324,0015888,00195312,001552,6218631,48198673,66 sacados/181
1234567ABCDEFGHIAnnéeNombred’utilisateursQuotientPourcentaged’augmentationnunRaison19953401996561,647111997921,6429219981451,5761319992431,6759420004141,70375 123ABCDEFGHIJn123456789coûtdunemètre135139,05coûttotaldenmètresforés135274,05 E.178 south America Nov 2004 12 points In the summer of 2003, France was hit by an excep-tional heatwave. Monsieur Dupont wants to dig a well at the bottom of his garden. A natural underground water reserve lies at 9 meters. He requests quotes for drilling the well. Quote n 1 Fixed price for taking charge, visit on terrain : 40 e VAT included. Fixed price per meter foré : 150 e incl. VAT Quote n 2 No fixed price for pick-up, but the price per meter depends on the depth reached : the first meter costs 135 e incl. VAT, each subsequent meter costs 3% more than the previous one. We’ll study these two quotes to estimate the cost of drilling a 9-meter well. Part A Quote study n 1 1 We note u 0 the takeover fee of 40 e and u n (for n 1 ) the total cost of n meter drilled. Thus : u 0 =40 and u 1 =190 . Calculate u 2 and u 3 2 a What type of growth does the drilling expense cor-respond to? b Justify that : u n =40+150 n 3 Then calculate the cost of a 9-meter borehole. Part B Quotation study n 2 1 We note v 1 the cost of the first meter drilled and v n the cost of the n-th meter drilled. Thus v 1 =135 . Show that : v 2 =139.05 . 2 a What type of growth does the drilling expense cor-respond to? b Justify that : v n = 135 × (1.03) n 1 3 Then calculate the total cost of drilling, we use the spreadsheet below : a What formula must be entered in cell D3 to obtain in each cell, after automatic copying to J3 , the cost of the n -th meter drilled? b What formula must be entered in cell D4 to obtain in each cell, after automatic copying to J4 , the total cost of n meters drilled? c Complete this table. Amounts will be rounded to the nearest cent. d What is the cost of a 9-meter borehole? E.174 In an imaginary country noted I , there is a capital P and a collection of villages V . As of 1 er January 2002, P and V had 200 000 and 300 000 inhabitants respectively. Each year, the population of P in-creases by 10 % , while that of V decreases by 20 000 inhabi-tants. 1 a As of 1 er January 2002, what percentage does the population of P represent compared to that of I ? b Calculate the population of P , that of V , then that of I at 1 er 2003. What percentage then does the population of P repre-sent in relation to that of I ? 2 Let n be a natural number. Let p n be the population of P at 1 er January (2002+ n ) ; thus p 0 =200 000 . a Express p n +1 as a function of p n and deduce the nature of the sequence ( p n ) . b Express p n as a function of n . Calculate p 5 . What does this value represent? 3 Let n be a natural number. Let v n be the population of V at 1 er January (2002+ n ) ; thus v 0 =300 000 . a Express v n +1 as a function of v n and deduce the nature of the sequence ( v n ) . b Express v n as a function of n . Calculate v 5 . What does this value represent? 4 This question involves the table given below. A spreadsheet gives in the column A the years from 2002 to 2007, in the column B the population of the capital P , in column C the population of all villages V and in column D the total population of the country I at 1 er January of the corresponding year. a Indicate the formulas that should be written in the cells D2 , A3 , B3 and C3 in order to obtain automati-cally, by copying down the years in the column A and the populations in the columns B , C and D . b Complete the table below. 5 a Graphically represent the evolution of the popula-tion of P and that of V by placing the points of co-ordinates ( n ; p n ) and ( n ; v n ) when the integer varies from 0 to 5. the graphical units will be 2 cm for one year on the x-axis and 1 cm for 10 000 inhabitants on the y-axis, which will be graduated from 200 000 in-habitants b Give the year x in which the population of P will ex-ceed that of V . c Assuming linear evolution of the populations of P and V qu during the year x , graphically determine the quar-ter qu in which the population of P will exceed that of V , showing all useful plots. https://chingmath.fr 1234567ABCDEFGHIAnnéeNombred’utilisateursQuotientPourcentaged’augmentationnunRaison19953401996561,647111997921,6429219981451,5761319992431,6759420004141,70375 sacados/178 123ABCDEFGHIJn123456789coûtdunemètre135139,05coûttotaldenmètresforés135274,05 sacados/174 Liban - juin 2005 - 12 points
1234567ABCDAnnéePopulationdePau1janvierPopulationdeVau1janvierPopulationdeIau1janvier2002200000300000 1234567891011121314151617181920212223ABCDProgrammmed’entraînementd’AlineProgrammmed’entraînementdeBlandineProgrammmed’entraînementdeCarolinePourcentaged’augmentation413;50%5%DistanceU(nparcourueparAlinen(enkm)DistanceV(nparcourueparBlandinelasemainen(enkm,arrondieà0,001)DistanceW(npar-courueparCar-olinelasemainen(enkm,ar-rondieà0,001)semaine1202020semaine22722,7semaine330,250semaine4semaine54833,19041,551semaine637,67147,628semaine76242,75754,010semaine86948,52960,710semaine955,08067,746semaine10semaine1182,889semaine129780,535semaine1399,586semaine14111103,747108,565semaine15118117,753117,993Distancetotaleparcourue1035841,849957,856Distancemoyenne6956,123 Distance(enkm)0123456789101112131415Semaine20406080100120 E.184 Aline, Blandine and Caroline de-cided to resume cycling training every Saturday for 15 weeks. Using a chart, each has drawn up her training program. They ride 20 km in the first week and want to do an outing together in the fifteenth week. The appendix reproduces the final state of the spreadsheet used. The values of some cells have been hidden. Part A Aline’s training program The distance covered by Aline each week is plotted on the graph in the appendix, and some distances appear in the col-umn B of the table. We note U ( n ) the distance covered in the n -th week. Thus : U (1)=20 ; U (15)=118 . 1 Using column values B and graph : a Conjecture the nature of the sequence of numbers U ( n ) . (Justify the answer given.] b Then express U ( n ) as a function of n for any integer n between 1 and 15. 2 Calculate the distance covered by Aline in the tenth week. 3 What formula, copied to the right, has she entered into cell B23 to calculate the average distance each traveled during the workouts? Partie B Blandine’s training program Blandine runs 20 km the first week. She wants to increase the distance covered each week by the same percentage so that the distance covered in the fifteenth week is, to the near-est unit, 118 km . To do this, she tested different percentages written in the cell C3 . 1 What formula did she enter in cell C7 and then copy down from C8 to C20 , knowing that the results updated automatically when she changed the weekly percentage increase? 2 Testing allowed her to find that a weekly increase of 13.5% is suitable. We note V ( n ) the distance Blandine traveled on the n -th week. a What is the nature of the sequence of numbers V ( n ) ? (Justify the answer given) b Express V ( n ) as a function of n , for any integer n be-tween 1 and 15. c How far does Blandine travel in the tenth week? 3 Calculate the percentage increase in distance traveled be-tween the first and fifteenth week. Part C Caroline training program Caroline runs 20 km in the first week. To calculate the dis-tances covered in subsequent weeks, she has entered the for-mula : in cell D7 =D6 × (1+$D$3)+$D$2 and copied it down from D8 to D20 . 1 The value in cell D7 has been hidden. What is this value? 2 What is the formula contained by the cell D8 ? 3 Note W ( n ) the distance travelled by Caroline on the n -th week. Is the sequence of numbers W ( n ) arithmetic? Is it geo-metric? Justify answers. 4 Calculate the average distance covered by Caroline dur-ing her training sessions. https://chingmath.fr 1234567ABCDAnnéePopulationdePau1janvierPopulationdeVau1janvierPopulationdeIau1janvier2002200000300000 sacados/184 1234567891011121314151617181920212223ABCDProgrammmed’entraînementd’AlineProgrammmed’entraînementdeBlandineProgrammmed’entraînementdeCarolinePourcentaged’augmentation413;50%5%DistanceU(nparcourueparAlinen(enkm)DistanceV(nparcourueparBlandinelasemainen(enkm,arrondieà0,001)DistanceW(npar-courueparCar-olinelasemainen(enkm,ar-rondieà0,001)semaine1202020semaine22722,7semaine330,250semaine4semaine54833,19041,551semaine637,67147,628semaine76242,75754,010semaine86948,52960,710semaine955,08067,746semaine10semaine1182,889semaine129780,535semaine1399,586semaine14111103,747108,565semaine15118117,753117,993Distancetotaleparcourue1035841,849957,856Distancemoyenne6956,123 Distance(enkm)0123456789101112131415Semaine20406080100120
1234567891011121314151617ABCDEFGHIEtudecomparativedesdeuxpropositionsdebailProposition1Proposition2AnnéesnunLoyerannuelCumuldesloyersannuelsvnLoyerannuelCumuldesloyersannuels2007040048004800400480048002008198164992979220092150485192149842010345454482049645053992038320114472566426160468561525998201254905880320404875840318382013650860963813650660743791220147526631244448526631644228201585446528509765476569507972016956267445772056968325762920171058069606468059271056473420181159871767185661673897212420191261673927924864076857980920201386856799287801 E.1967 Mr and Mrs X are planning to rent an apartment for a few years. The landlord is offering them two types of lease from 1 er Jan-uary 2007. Proposal 1: to 1 er January 2007, the monthly rent is 400. This monthly rent remains un-changed during 2007 and will be subject to an increase of 18 on the first of January of each subsequent year. Proposal 2: to 1 er January 2007, the monthly rent is 400. This monthly rent remains un-changed during 2007 and will be subject to an increase of 4 % on the first of January of each of the following years. Mr and Mrs X study and compare the two proposals using an automated spreadsheet given in Appendix 1. The format of the cells is such that the values displayed are rounded to the unit. 1 Study of the proposal 1 Mr. and Mrs. X decide to note u n the amount in eu-ros of the monthly rent they will be charged during the year (2007+ n ) , where n denotes a natural number, if they choose proposition 1. Thus : u 0 =400 a Calculate u 1 and u 2 . b What is the nature of the sequence ( u n ) ? c Express u n as a function of n , for any natural number n . d How much will the monthly rent be in 2020 with pro-posal 1? e What formula did Mr. and Mrs. X write in cellcould they write in cell C5 and automatically copy down to calculate in column C the first terms of the sequence ( u n ) ? Complete the cells C5 , C6 , C17 of the table in ap-pendix 1 . 2 Proposal study 2 Mr. and Mrs. X decide to note v n the amount in euros of the monthly rent they will be charged during the year (2007+ n ) , where n denotes a natural number, if they choose proposition 2. Thus : v 0 = 400 . a Calculate v 1 and v 2 . Round to the nearest whole num-ber. b Justify that the sequence ( v n ) is a geometric sequence whose reason will be specified. c Justify that for any natural number n , we have : v n =400 × 1.04 n . d What will the monthly rent be in 2020 with proposal 2? Round to the nearest whole number. e Complete the cells G5 , G6 , G17 of the table in ap-pendix 1 . 3 Annual rents per proposal 1 a In column D , Mr and Mrs X have calculated the amount of annual rent due, if they choose proposal 1, for each of the years shown in column A . What formula could they have written in cell D4 and automatically copied down for it? Complete the cells D5 , D6 , D17 of the table in the appendix. Mr and Mrs X have similarly calculated, in the columns H and I of the table in the appendix, annual rents and cumulative annual rents corresponding to proposal 2. 4 a Mr and Mrs X plan to rent the apartment for 5 years from January 1, 2007. Which lease proposal should they choose? Justify. b After how many full years of rental (starting 1 er Jan-uary 2007) is proposal 1 more advantageous than pro-posal 2?est-elle plus avantageuse que la proposition 2? https://chingmath.fr sacados/1967 1234567891011121314151617ABCDEFGHIEtudecomparativedesdeuxpropositionsdebailProposition1Proposition2AnnéesnunLoyerannuelCumuldesloyersannuelsvnLoyerannuelCumuldesloyersannuels2007040048004800400480048002008198164992979220092150485192149842010345454482049645053992038320114472566426160468561525998201254905880320404875840318382013650860963813650660743791220147526631244448526631644228201585446528509765476569507972016956267445772056968325762920171058069606468059271056473420181159871767185661673897212420191261673927924864076857980920201386856799287801
12345678910ABCDAnnéenun20000210152001122520022200332004420055200663002007720088 01234567150200250300350 12345678ABCAnnéenvn20060310200712008220093201042011520126402 E.1906 Both parts are independent In a media library, the management wishes to renew the stock available for loan (notament en cedéroms, DVDs) and increase the number of computers (with Internet access) avail-able to the public. One of the solutions being explored to find the financial means to meet this demand is to increase mem-bership. Part 1: Study of the evolution of the number of mem-bers First, we study the evolution of the number of members as a func-tion of time. We call u 0 the num-ber of members for the year 2000 and u n the number of members for the year (2000+n) . The table and graph below represent the evolution of the number of mem-bers between 2000 and 2006. 1 According to the graph, what type of growth does the se-quence ( u n ) correspond to? Note that the sequence ( u n ) is an arithmetic sequence of reason 15 and first term u 0 =210 . 2 a Calculate u 2 . b Express u n +1 as a function of u n . c Express u n as a function of n and u 0 . 3 In cell D2 , we have placed the reason for the sequence. a What formula could be written in cell C4 , using cell D2 , then copy down to C10 , to calculate the terms of the sequence? b If this growth model holds until 2008, what will be the number of members in 2008? Part 2: Planning a marketing study Management decides to slightly reduce membership fees to further encourage membership growth. A marketing study estimates that with these new rates, membership will increase by 5 % per year after 2006. We call v 0 , the number of members in 2006 and v n , the number of members in (2006+ n ) . 1 a Calculate v 1 , v 2 . Give the rounding to unity of these values. b To what type of growth does the sequence ( v n ) corre-spond? c Specify the nature and reason of the sequence ( v n ) . d Show that, for any natural number n : v n = 300 · 1.05 n . 2 What formula can be used in cell C3 , then copied down to C8 to calculate the forecast number of members? 3 Calculate the percentage increase in membership be-tween 2006 and 2012. 2. Unclassified financial years E.1828 the four parts of this exercise can be treated independently of each other. Part A : The different types of family with at least one child under 5 in 1990 and 1999 (document 1 in appendix 1) 1 Interpret with a sentence each of the two values entered in cells E7 and F4 of the document in Appendix 1. 2 Why is the sum of the five percentages entered in cells E4 to E8 on document 1 not equal to 100? 3 Calculate the three missing values a , b and c from Doc-ument 1. (numbers of families will be rounded to the thousand and percentages to 0.1 % ) Part B: Number of children and family types in 1999 (Doc-ument 2 in Appendix 1) 1 According to Document 2 in Appendix 1, what share do families with two or more children represent among ˇtra-ditionalı families, in 1999? 2 a By reading documents 1 and 2, give : the percentage of ˇtraditionalı families among all families in 1999, the percentage of one-child families among ˇtradi-tionalı families in 1999. b Deduct the percentage share represented by ˇtradi-tionalı families with one child among all families in 1999. Part C : Spreadsheet work In Appendix 1, Document 1 is an automated spreadsheet. The numbers of families have been previously entered on this spreadsheet and formulas have been used to calculate the per-centages of columns C , E and F (some of the percentages ob-tained are given) . 1 Give the formula to be entered in cell C4 and which, when copied down, to C8 , will give all the column percentages C . https://chingmath.fr sacados/1906 12345678910ABCDAnnéenun20000210152001122520022200332004420055200663002007720088 01234567150200250300350 12345678ABCAnnéenvn20060310200712008220093201042011520126402 chapExoCorrec/1828 sacados/1828
12345678ABCDEF19901999Evolutionde1990à1999(en%)Nombreen%Nombreen%Ensembletotaldesfamilles9126000100,08822000100,0-3,3Famillesˇtraditionnellesı7083000a647400073,4-8,6Famillesmonoparentales139700015,3164000018,6bFamillesrecomposées6460007,17080008,09,6-dontaucunenfantn’estducoupleactuelcd3280003,75,8-dontaumoinsunenfantestducoupleactuelef3800004,313,1 1020304050601enfant2enfant3enfant4enfantsouplus1enfant2enfant3enfant4enfantsouplus1enfant2enfant3enfant4enfantsouplus404015556281052837241Famille"traditionnelles"FamillesmonoparentalesFamillesrecomposées 1234567891011ABCDEAnnéePopulationTaux d’évolutionarrondi à0;1%nun19502500×025001960301420;6%11970368322;2%21980445320;9%31990520142000608056789 2 Similarly, give the formula to be entered in cell F4 and which when copied down to F8 , will give all the percent-ages in column F . Part D: Changes in the number of blended families 1 Between 1990 and 1999, the annual increase in the num-ber of blended families was 1.02 % . Verify that over this period this number of families has increased by approxi-mately 9.6 % . It is now assumed that the annual evolution of 1.02 % continues beyond this period. 2 We note u 0 the number of blended families in 1990 ( u 0 =646 000 ) , and u n their number, n years later, in 1990+ n . a What is the nature of the sequence ( u n ) ? Justify the answer and specify its reason. b Express u n as a function of n . 3 How many stepfamilies can we estimate in 2005? Document 1 Source : Surveys ˇFamily history studyı 1990 and 1999, Insee Document 2: Nombres children by family type in 1999 Reading example: 11 % of blended families have 4 or more children ; this is the case for 5 % traditional families and 5 % single-parent families. Source : Enquête ˇÉtude de l’histoire familialeı 1999, Insee E.548 The parts A et B are independent. Part A In Albert Jacquard’s book ˇ The Time of the Finite World Has Come ı , the following statement appears : A population increase of 2 % per year may seem very small, yet it corresponds to a doubling in 35 years, thus a quadru-pling in 70 years, and a multiplication by 7 in less than a century. Are the author’s statements correct? Justify your answer. Part B 1 The following worksheet, taken from a spreadsheet, shows the world population in millions: What formula should be entered in C3 to complete col-umn C by copying this formula down? 2 a Calculate the overall growth rate of the world pop-ulation between years 1950 and 2000 . b Show that the average rate of change per decade between the years 1950 and 2000 is approximately 19 ; 45 % . 3 Consider the geometric sequence u with first term u 0 = 2500 and common ratio q =1 ; 195 . a What formula, to be copied down, can be written in E3 to calculate the terms of the sequence u ? b If we assume that the world population will grow at the same rate beyond the year 2000 , we can estimate that the world population in the year (1950+10 n ) will be approximately equal to the term u n of this sequence What population can we therefore predict for the year 2010 ? For the year 2050 ? c By how much would the world population thus increase in a century? https://chingmath.fr 12345678ABCDEF19901999Evolutionde1990à1999(en%)Nombreen%Nombreen%Ensembletotaldesfamilles9126000100,08822000100,0-3,3Famillesˇtraditionnellesı7083000a647400073,4-8,6Famillesmonoparentales139700015,3164000018,6bFamillesrecomposées6460007,17080008,09,6-dontaucunenfantn’estducoupleactuelcd3280003,75,8-dontaumoinsunenfantestducoupleactuelef3800004,313,1 1020304050601enfant2enfant3enfant4enfantsouplus1enfant2enfant3enfant4enfantsouplus1enfant2enfant3enfant4enfantsouplus404015556281052837241Famille"traditionnelles"FamillesmonoparentalesFamillesrecomposées chapExoCorrec/548 sacados/548 1234567891011ABCDEAnnéePopulationTaux d’évolutionarrondi à0;1%nun19502500×025001960301420;6%11970368322;2%21980445320;9%31990520142000608056789
Année1989199019911992199319941995Nombredepoissonsenmilliers0123456 E.177 Scientists want to study the long-term evolution of a fish population in a small river. To do this, they have the results of counts carried out in a portion of this river between 1990 and 1994. The table and graph below give the numbers found per year from 1990 to 1994. Year Number of fish 1990 5150 1991 4840 1992 4570 1993 4250 1994 3960 1 A first scientist suggests modeling the evolution of fish numbers by an arithmetic sequence. Why does the graph suggest that an arithmetic sequence might be suitable? 2 This first scientist chooses to model the evolution of the number of fish by the arithmetic sequence ( u n ) of reason r = 300 and first term u 0 =5150 . Thus, u n represents the number of fish in the year (1990+ n ) . a What interpretation can be given to the reason for this sequence for the fish population? b Express u n as a function of n . c Calculate the population size predicted by this model in 2004. 3 A second scientist is not convinced by this model and proposes for this population an exponential evolution. Indeed, he notes that : 4840 5150 4570 4840 4250 4570 3960 4250 0.935. He then chooses to model the evolution of the number of fish by the geometric sequence ( v n ) , of reason q =0.935 and of first term v 0 =5150 . Thus, v n represents the number of fish in the year (1990+ n ) . a What is the percentage annual decline in fish numbers according to this model? b Express v n as a function of n . c Calculate v 14 . The result will be rounded to the unit. 4 In 2004, a count was carried out and 1980 fish were recorded in the section of river studied. a Which of the two models proposed above is the more relevant? Justify your answer. b We choose to use the model proposed by the second scientist. Calculate v 30 and v 40 (results will be rounded to unity) . Determine the year from which the fish population will fall below 500 individuals. E.1897 Mr and Mrs Dupond wish to bor-row 200 000 e to buy a house. They are studying proposals from two banks for 15-year loans starting 1 er January 2007. The monthly repayments on the loan offered by Crédit du Soleil bank are 1 500 e for the entire duration of the loan. The monthly repayments on the loan offered by Caisse Azur bank are 1 230 e in the first year and increase by 3 % each year. 1 In this question, we’re interested in the loan offered by the bank Crédit du Soleil. a What is the total amount that Mr and Mrs Dupond will have to pay to the bank Crédit du Soleil in 2007 if they take out this loan? b After 15 years, how much will Monsieur and Madame Dupond have repaid if they take out this loan? This sum is called real value of the loan . 2 In this question, we are interested in the loan offered by the Caisse d’Azur bank. Results will be rounded if necessary to the euro cent. a Calculate the monthly repayments that Mr and Mrs Dupond will have to make in 2008 if they take out this loan. We note u 0 the amount in euros of the monthly payments in 2007, u 1 the amount in euros of the monthly payments in 2008 and, more generally, u n the amount in euros of monthly installments in 2007+ n , n being an integer be-tween 0 and 14. Thus : u 0 = 1 230 . b Give u 1 . Calculate u 2 . c What is the nature of the sequence ( u n ) ? Justify your answer. d Express u n as a function of n for integers n between 0 and 14. How much will Monsieur and Madame Dupond’s monthly payments be in 2016 if they take out the loan offered by Caisse Azur bank? e A graphical representation of the sequence ( u n ) , for integers between 0 and 14, is given in annexe . Determine graphically, from which year onwards the monthly repayments requested from Mr and Mrs Dupond by the Caisse Azur bank will be higher than those requested by the Crédit du Soleil bank. 3 Before making their choice for either of the two banks, Monsieur and Madame Dupond also want to know the real value of the loan proposed by the Caisse Azur bank. to do this, they use a table. We give in appendix 1 their spreadsheet, in which the contents of some boxes have been hidden. a Complete boxes C3 , C4 , D2 , D3 and D4 of the table given in annexe . No justification is required. b Which formula may have been written in cell C3 to ob-tain, after copying down to cell C16 , the terms of the https://chingmath.fr chapExoCorrec/177 sacados/177 Année1989199019911992199319941995Nombredepoissonsenmilliers0123456 sacados/1897
012345678910111213141300140015001600170018001900 1234567891011121314151617ABCDRangnAnnéenMensualitéunversésàlabanqueCaisseAzurMontantannuelverséàlabanqueCaisseAzur020071230,001200822009320101344,0516128,65420111384,3816612,51520121425,9117110,89620131468,6817624,21720141512,7418152,94820151558,1319697,539201619258,451020171653,0219836,211120181702,6120431,291220191753,6921044,231320201806,3021675,561420211860,4922325,82152022Valeurduprêt274519,97 1234567891011121314151617181920ABCDAnnéeRangdutermedechaquesuiteCompted’UrbainSuiteun:TireliredeVictorSuitevn200003000,01000,00200113082,501240,00200223167,271480,00200333254,371720,00200443343,861960,00200553435,822200,00200663530,312440,00200773627,392680,00200883727,142920,00200993829,643160,002010103934,953400,002011114043,163640,00201212201313201414201515201616201717201818 sequence ( u n ) in column C ? c Which formula may have been written in cell D2 to obtain, after copying down to cell D16 , the amount of money paid into column D ? d Mr and Mrs Dupond have calculated in cell D17 the real value of the loan offered to them by the bank Caisse Azur. What formula could they write in cell D17 for this? E.1886 On January 1, 2000, two babies were born : Urbain and Victor. Their respective families de-cide to save for their child. Urbain’s family pays 3 000 euros on the day their sons are born, into an account where the annual interest rate is 2.75 % . No withdrawals or deposits are made in subsequent years. The interest rate remains fixed. Victor’s family places 1 000 euros in a piggy bank on 01 = 01 = 2000 and then pays in, every first January thereafter, 240 euros without ever making a withdrawal. 1 Calculate the money available in each child’s account on their first birthday. We call u n the amount in euros in Urbain’s account on the first of January in the year 2000+ n . We call v n the amount in euros in Victor’s piggy bank on the first of January in the year 2000+ n . In the table below, the situation has been represented in a spreadsheet. 2 a What formula can we write in cell C3 if we want to obtain by copying down the values of the sequence ( u n ) ? b Which formula then contains the cell C7 ? 3 a What formula can we write in cell D3 if we want to obtain by copying down the values of the sequence ( v n ) ? b Which formula then contains the cell D8 ? 4 a What is the nature of the sequence ( u n ) and its char-acteristic elements? b Express u n as a function of n . c What is the nature of the sequence ( v n ) and its char-acteristic elements? d Express v n as a function of n . 5 Complete the table in Appendix 2. 6 On what anniversary date will Victor have more money in his piggy bank than Urbain has in his account? 7 Victor can dispose of all the money in his piggy bank af-ter his eighteenth birthday. His family continues to make annual payments. a With the sum available in his piggy bank, will he be able to buy a car worth 6 000 euros from January 2, 2018? b Determine the minimum number of years required for his piggy bank to have a sufficient balance to buy the car? https://chingmath.fr 012345678910111213141300140015001600170018001900 1234567891011121314151617ABCDRangnAnnéenMensualitéunversésàlabanqueCaisseAzurMontantannuelverséàlabanqueCaisseAzur020071230,001200822009320101344,0516128,65420111384,3816612,51520121425,9117110,89620131468,6817624,21720141512,7418152,94820151558,1319697,539201619258,451020171653,0219836,211120181702,6120431,291220191753,6921044,231320201806,3021675,561420211860,4922325,82152022Valeurduprêt274519,97 sacados/1886 1234567891011121314151617181920ABCDAnnéeRangdutermedechaquesuiteCompted’UrbainSuiteun:TireliredeVictorSuitevn200003000,01000,00200113082,501240,00200223167,271480,00200333254,371720,00200443343,861960,00200553435,822200,00200663530,312440,00200773627,392680,00200883727,142920,00200993829,643160,002010103934,953400,002011114043,163640,00201212201313201414201515201616201717201818