Grade 10 / product inequalities and sign tables 55 exercises (100% corrected)

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-4-2024-4-224Cf -6-4-202-2246Cg -6-4-20246-4-224Cf -6-4-20246-4-224Cg xOyx0(dCoe`cientdirecteurpositif(m>0)xOyx0(dCoe`cientdirecteurnégatif(m<0)xSignedef(x−∞x00xSignedef(x−∞x00 ChingQuizz : 9 exercises available for Quizz assessment : 1. Graphical reading of sign tables E.472 Shown below are the graphical rep-resentations of the functions f and g defined respectively on [ 4 ; 4] and [ 6 ; 2] . 1 Determine, graphically, the solutions of the inequations : f ( x ) 0 ; g ( x ) 0 2 Draw up the sign tables for the functions f and g : x 4 4 f ( x ) x 6 2 g ( x ) E.481 Consider the two functions f and g defined on 6 ; 6 whose graphical representations are given below : Draw up the sign tables of the functions f and g on 6 ; 6 2. Sign table of affine functions E.9784 Proposal: 1 Consider the linear function f defined by: f ( x ) = 2 x + 3 Determine the sign table of the function f . 2 Consider the linear function f defined by: g ( x ) = x + 1 Determine the sign table of the function g . E.9785 1 a Consider the function f affine defined by: f ( x ) = 3 x 4 Complete the sign table for the function f : x −∞ + f ( x ) b Consider the function g affine defined by: g ( x ) = 2 x + 1 Complete the sign table for the function g : x −∞ + g ( x ) 2 Let h be the function obtained by the product of the functions f and g . That is, for any x R : h ( x ) = f ( x ) × g ( x ) Specify whether the following statements are true or false : a h ( 5) is positif b h ( 1) is positif c h (1) is positif d h (3.2) is positif E.9786 Consider an affine fonctin f defined on R and whose sign table is given below : x −∞ 1 2 + f ( x ) + 0 Furthermore, the inequation f ( x ) 3 admits for solutions the set S : S = −∞ ; 3 Determine the slope-intercept formof the function f . https://chingmath.fr chapExoCorrec/472 sacados/472 -4-2024-4-224Cf -6-4-202-2246Cg chapExoCorrec/481 sacados/481 -6-4-20246-4-224Cf -6-4-20246-4-224Cg chapExoCorrec/9784 sacados/9784 xOyx0(dCoe`cientdirecteurpositif(m>0)xOyx0(dCoe`cientdirecteurnégatif(m<0)xSignedef(x−∞x00xSignedef(x−∞x00 chapExoCorrec/9785 sacados/9785 chapExoCorrec/9786 sacados/9786
-122--122--122-2x1x2(2xx ---3x43xg(x 3. Construction of sign tables E.468 1 Consider the function f defined by the relation: f ( x ) = 2 x 2 3 x 2 In this question, we will study the sign of the function f . a Establish equality: f ( x )=(2 x +1)( x 2) . b Solve the following two inequations : 2 x + 1 < 0 ; x 2 < 0 c In the table below and for the two factors 2 x +1 and x 2 , color: in blue the intervals over which the factor is positive ; in red the intervals over which the factor is negative. d Complete the third line using the sign rule for a prod-uct. e Solve the inequation : f ( x ) 0 . 2 Consider the function g whose image of a number x is given by the relation: g ( x ) = 3 x 2 + 13 x 12 a Establish the following equality: g ( x )=(3 x 4)(3 x ) b As in the previous question, complete the table below : c Deduce the set of solutions to the inequation g ( x ) < 0 E.469 1 a Solve at R the following inequations : 4 2 x 0 ; 5 x + 15 0 b Deduce the solutions of the inequations : 4 2 x < 0 ; 5 x + 15 < 0 2 a In the first two lines of the sign table, indicate the sign of the expressions on R : x −∞ + 4 2 x 5 x +15 (4 2 x )(5 x +15) b Complete the third row of the table to indicate the sign of the product (4 2 x )(5 x +15) on R . c Deduce the set of solutions to the inequation : (4 2 x )(5 x + 15) 0 E.4380 Consider the functions f and g whose images of the number x are respectively defined by: f ( x ) = 2 x × x 5 ; g ( x ) = (2 x )( x 5) 1 a Justify that the function f is not defined for the number 3 . b Determine the definition set of the function f . 2 a Determine the image of the number 3 by the func-tion g . b Determine the definition set of the function g . 4. Product Specifications Table E.4455 Complete the sign tables below : 1 x −∞ + 2 x + 1 3 + x (2 x +1)(3+ x ) 2 x −∞ + 2 x 4 x 3 (2 x )(4 x 3) E.4876 Complete the sign tables below : 1 x −∞ + 1 x 2 x + 1 (1 x )(2 x +1) 2 x −∞ + x 3 2 x + 4 ( x 3)( 2 x +4) https://chingmath.fr chapExoCorrec/468 sacados/468 -122--122--122-2x1x2(2xx ---3x43xg(x chapExoCorrec/469 sacados/469 chapExoCorrec/4380 sacados/4380 chapExoCorrec/4455 sacados/4455 chapExoCorrec/4876 sacados/4876
E.460 Establish the sign table for algebraic expressions : a ( x + 1)(2 x ) b (2 x + 4)( x 2) c ( x + 1) 2 E.11648 Construire le tableau de signes de cha-cune des expressions ci-dessous : a (2 x 15)(2 x 3) b x ( x + 1) E.11650 Construire le tableau de signe des ex-pressions : a ( 2 x 1)( x + 1) b ( x + 2)( x + 3) 5. Table of Signs for a Quotient E.9787 Complete the sign tables below : 1 x −∞ + x + 5 2 x 8 x + 5 2 x 8 2 x −∞ + x 1 4 x x 1 ( x 1)(4 x ) x 1 E.9788 Complete the sign tables below : 1 x −∞ + 2 + x 2 x 2 + x 2 x 2 x −∞ + 4 x + 1 x 1 x (4 x +1)( x 1) x E.11712 Construire le tableau de signe des ex-pressions : a 5 x 3 4 x + 7 b 2 x + 5 6 x + 15 6. Inequations and sign tables E.480 Solve the following inequalities: a ( x + 4)(1 2 x ) 0 b 3 + x 2 x 0 E.9819 Solve the following inequalities: a (3 2 x )(5 x + 2) 0 b (3 x + 1)(4 2 x ) 0 E.9790 Solve the inequation : ( x + 1)( x 2) 1 x > 0 E.9820 Solve inequalities: a (5 2 x )( x 1) 3 x 2 > 0 b (2 x + 1) 2 (4 x 3)(1 2 x ) 0 E.465 1 Expand : (2 x + 1)( x 1) 2 Solve the following inequation : 2 x 2 x 1 x 2 + 1 0 . E.442 1 Expand : ( x 1)( x 5) 2 Solve : ( x 3) 2 4 3 2 x < 0 Hint: we will use the result of question 1 E.445 Consider the function f defined by the following relationship : f : x ↦− x + 1 2 x 2 + 7 x 3 1 Establish the following equality: 2 x 2 + 7 x 3 = (2 x 1)(3 x ) 2 Give the definition set of the function f . 3 a Draw up the sign table for the function f on its def-inition set. b Solve the inequation : f ( x ) 0 E.11713 Résoudre les inéquations suivantes : a ( x + 4)(5 2 x ) 0 b (3 x )(3 6 x ) < 0 E.11714 Résoudre les inéquations suivantes : a 5 x + 2 x 3 0 b 5 2 x x + 4 0 https://chingmath.fr chapExoCorrec/460 sacados/460 chapExoCorrec/11648 sacados/11648 chapExoCorrec/11650 sacados/11650 chapExoCorrec/9787 sacados/9787 chapExoCorrec/9788 sacados/9788 chapExoCorrec/11712 sacados/11712 chapExoCorrec/480 sacados/480 chapExoCorrec/9819 sacados/9819 chapExoCorrec/9790 sacados/9790 chapExoCorrec/9820 sacados/9820 chapExoCorrec/465 sacados/465 chapExoCorrec/442 sacados/442 chapExoCorrec/445 sacados/445 chapExoCorrec/11713 sacados/11713 chapExoCorrec/11714 sacados/11714
-2-1234I-12JOCf -6-5-4-3-2-12345678I-123JOCg x-6-5-4-3-2-10123y-2-1123Cf -3-2-10123-4-224Cf 7. Graphical solutions to inequalities and sign chart E.5027 Consider the function f defined on the interval 2 ; 4 , whose representative curve C f is given in the orthonormal coordinate system O ; I ; J below : 1 We will leave the construction lines necessary for solving the following questions : a Graphically determine the image of the number 2 by the function f . b Graphically determine the antecedents of the number 1 by the function f . 2 a Graphically determine the set of solutions to the in-equality f ( x ) 0 b Complete the sign table for the function f : x f ( x ) E.365 In an orthonormal coordinate system ( O ; I ; J ) , consider the curve C g representing the function g : 1 Give, without justification, the domain of the function g . 2 a Graphically, solve the equation f ( x )=0 . b Complete the sign table for the function f . x f ( x ) E.9656 Consider a function f whose rep-resentative curve C f is given in the orthonormal coordinate system below : 1 Give the domain of the function f . 2 a Graphically, give the solutions to the equation f ( x )=0 . b Draw up the sign table for the function f . 8. Graphical readings and algebraic manipulations E.458 Consider the function f defined on R by the relation: f ( x ) = x 3 3 x + 2 1 Graphically, determine the set of solutions to the inequa-tion f ( x ) > 0 . https://chingmath.fr chapExoCorrec/5027 sacados/5027 -2-1234I-12JOCf chapExoCorrec/365 sacados/365 -6-5-4-3-2-12345678I-123JOCg chapExoCorrec/9656 sacados/9656 x-6-5-4-3-2-10123y-2-1123Cf chapExoCorrec/458 sacados/458 -3-2-10123-4-224Cf
-2-10123-4-224Cf -7-6-5-4-3-2-1234567I-4-3-2-1234JOCfCg -2-1234I-224JO 2 a Establish the following equality: f ( x )=( x +2)( x 1) 2 b Draw up the sign table for the function f at R . c Deduce the set of solutions to the inequation : f ( x ) > 0 E.446 Consider the function f whose image of a number x is defined by the expression : f ( x ) = x 3 + 2 x 2 + x 2 In the plane provided with an orthogonal reference frame, we have drawn the curve C f representative of the function f : 1 By graphical reading, give the intervals over which the function f is strictly positive. 2 Show the equality: x 3 +2 x 2 + x 2= ( x 2)( x 2 1) 3 a Draw up the table of signs for f . b Deduce the solutions of the inequation : f ( x ) > 0 . 9. Relative positions of curves: graphic resolution E.462 In the plane provided with a refer-ence frame O ; I ; J , consider the two curves C f and C g rep-resentative respectively of the functions f and g defined on 7 ; 7 : 1 Determine, graphically, the coordinates of the intersec-tion points of the curves C f and C g . 2 Graphically, solve the inequation : g ( x ) f ( x ) E.372 Consider the function f whose rep-resentation is given below in the orthogonal reference frame O ; I ; J ) : We are interested in the affine function g defined by the rela-tion : g : x ↦− x + 1 1 Draw the representative curve of the function g in the above reference frame. 2 Graphically, solve the equation : f ( x )= g ( x ) . 3 Graphically solve the inequation : f ( x ) g ( x ) https://chingmath.fr chapExoCorrec/446 sacados/446 -2-10123-4-224Cf chapExoCorrec/462 sacados/462 -7-6-5-4-3-2-1234567I-4-3-2-1234JOCfCg chapExoCorrec/372 sacados/372 -2-1234I-224JO
-4-3-2-1234I-3-2-1234JOCfCg -2-1234I-6-5-4-3-2-123JOCfCg 1xyx141 E.2142 In the plane provided with an or-thonormal reference frame, we give the representative curves of the functions f and g defined on the interval [ 4 ; 4] : Consider the inequation : f ( x ) <g ( x ) 1 Which of the numbers below are solutions of this inequa-tion : a 2.5 b 0.25 c 1 2 Solve this inequation graphically. 10. Relative positions of curves: algebraic solution E.4915 1 In the plane provided with a reference frame O ; I ; J orthogonal, consider the representative curves C f and C g representative of the functions f and g . Solve grahpically on the interval 2 ; 4 the following inequation : f ( x ) <g ( x ) 2 The functions f and g are defined on R by the expres-sions : f ( x ) = x 3 3 x 2 x + 1 ; g ( x ) = x 2 + 2 x + 1 a Determine the expression of the polynomial P of degree 1 verifying the equality: x 3 2 x 2 3 x =( x 2 3 x ) × P b Deduce on which intervals the curve C g is strictly above C f . E.8192 In the plane provided with a refer-ence frame O ; I ; J orthogonal, consider the representative curves C f and C g representative of the functions f and g where the functions f and g are defined by: f ( x ) = 6 x 3 + 2 x 2 + x + 1 ; g ( x ) = 2 x 2 + 19 x + 13 1 Determine the reals a and b realizing the identity: 6 x 3 18 x 12=(2 x +2)(3 x +3)( ax + b ) 2 Deduce on which intervals the curve C g is strictly above C f . 11. Problems E.2868 A manufacturer of cardboard boxes uses rolls to produce a 41 cm wide strip of cardboard from which he traces and cuts out box patterns before gluing them on. He arranges his patterns as shown in the drawing below : https://chingmath.fr chapExoCorrec/2142 sacados/2142 -4-3-2-1234I-3-2-1234JOCfCg chapExoCorrec/4915 sacados/4915 -2-1234I-6-5-4-3-2-123JOCfCg chapExoCorrec/8192 sacados/8192 chapExoCorrec/2868 sacados/2868 1xyx141
x9cm4cmABCDEF 5m10mxABCDEFG The boxes, in the shape of straight blocks, have two x cm -square faces, fitted with two 1 cm -wide tabs for gluing, and four other faces whose dimensions in cm are x and y , as well as a flap for closure. 1 a Give an expression for y as a function of x . b Justify that the value of x belongs to the interval 0 ; 19.5 . 2 Demonstrate that the volume V , in cm 3 , of the box is given, as a function of x , by the formula : V = 39 x 2 2 x 3 3 a Determine the expression of the polynomial P veri-fying the equality: 39 x 2 2 x 3 972 = ( x 18)( x 6) × P b Deduce the values of x for which the volume V is greater than 972 cm 3 . 4 a Determine the expression of the polynomial Q veri-fying the equality: V ( x ) 2197=( 2 x 13) × Q b Deduce the sign table for the expression : V ( x ) 2197 . c Give the maximum volume the manufacturer can ob-tain with this type of box; for what value of x is this maximum reached? E.1979 Consider the triangle ABC right-angled A such that : AB = 9 cm ; AC = 4 cm Consider a point D belonging to segment [ AB ] and note x the length of segment [ BD ] . From the point D we construct a rectangle DEFA such that : E [ BC ] ; F [ AC ] Note A the area of the rectangle DEFA . 1 a Determine the expression for length FA as a func-tion of x . b Justify, briefly, that the real number x belongs to the interval 0 ; 9 . 2 Establish that the area A is expressed as a function of x by: A ( x ) = 4 x 4 9 · x 2 3 a Draw up the table of variations of the function A on the interval 0 ; 9 . b What is the maximum area reached by the A area? 4 We wish to know the values of x for which the area A has greater than or equal to 5 cm 2 : a Establish the following factorization : 4 x 2 + 36 x 45 = (2 x 15)(3 2 x ) b Solve the inequation : A ( x ) 5 . E.11721 1 a Etablir la factorisation : 3 x 2 +10 x 3=( x 3)(1 3 x ) b Résoudre l’inéquation: 3 x 2 + 10 x 3 > 0 2 On considère la figure ci-dessous composée des deux rect-angles ABCD et AEFG : Déterminer pour quelle valeur de x , l’aire de la partie hachurée est strictement supérieure à 53 m 2 . https://chingmath.fr chapExoCorrec/1979 sacados/1979 x9cm4cmABCDEF chapExoCorrec/11721 sacados/11721 5m10mxABCDEFG
3m9mxABCDEFG ABCDEFGHI2xx4cm4cm 11x211x·(1x2·(1x122x12x12x E.11722 1 a Etablir la factorisation : 2 x 2 +9 x 10=( x 2)(5 2 x ) b Résoudre l’inéquation: 2 x 2 + 9 x 10 0 2 On considère la figure ci-dessous composée des deux rect-angles ABCD et AEFG : Déterminer pour quelle valeur de x , l’aire de la partie hachurée est strictement supérieure à 37 m 2 . E.11723 1 a Etablir la factorisation : 4 x 2 12 x + 27 4 = 4 x 9 x 3 4 b Résoudre l’inéquation: 4 x 2 12 x + 27 4 0 2 On considère la figure ci-dessous composée : du carré AEFG , de deux rectangles ABCD et CIFH . Les points B , D , I , H ap-partiennent aux côtés du carré AEFG . On considère le domaine grisé représen ci-contre et on note son aire A : (les mesures sont exprimées en centimètre) Déterminer l’ensemble des valeurs de x réalisant l’inéquation: A 37 4 Indication : toute trace de recherche ou de prise d’initiative sera prise en compte dans l’évaluation. 12. Deepening: reflection on algebraic operations E.471 Here’s a student’s solution to an in-equation : 1 is 2 the solution to the inequation : 1 1+ x 2 ? ab What can we deduce from the proposed resolution? 2 We break down the student’s resolution, indicating the algebraic manipulation performed at each step by the student. Complete the diagram below : 3 a What can be the sign of the expression 1+ x ? b Deduce the error made by the student. 4 Solve the inequation : 1 1+ x 2 E.479 A student has produced the following solution to an inequation : 1 is the number 1 solution of the inequation : x 2 + 4 x 4 ab What can we deduce about the student’s proposed resolution? 2 Solve this inequation correctly. https://chingmath.fr chapExoCorrec/11722 sacados/11722 3m9mxABCDEFG chapExoCorrec/11723 sacados/11723 ABCDEFGHI2xx4cm4cm chapExoCorrec/471 sacados/471 11x211x·(1x2·(1x122x12x12x chapExoCorrec/479 sacados/479
13. Further study: systems of inequalities E.319 Give the value of a so that the system below has as its solution the interval 1 ; 3 : 3 x + 2 5 1 2 x a E.318 Three real numbers a , b and c verify the following system : a · b · c < 0 a · b > 0 a + b > 0 Find the sign of these three numbers. E.348 Solve the following systems of equa-tions : 1 2 x 3 < 5 x 1 x + 4 3 x 2 2 3 x 3 > x + 1 2 x + 1 2 x + 1 14. Deepening: manipulation of frames E.317 Consider a ABCD square with 5 cm sides. 1 Give the exact length of the diagonals of this square. 2 Knowing that : 1.41 < 2 < 1.42 Give a frame for the length of this diagonal. E.315 1 Let a R such that 1 2 <a< 1 , specify which frames are verified by a : a 1 2 < 1 a < 2 b 0 <a < 2 a c 1 4 <a 2 < 4 2 By case disjunction for a 1 ; 0 and a 0 ; 2 , give a frame for a 2 and a 3 for 1 <a< 2 . 15. Unclassified exercises E.470 When solving an equation or inequal-ity, the ˇ domain of solution ı ı is the set of values that the unknown x can take. We will then look for solutions among the values in the solution set. 1 Here is a student’s solution to equation x 2 =3 x : ( E ) : x 2 = 3 x x 2 x = 3 x x x = 3 From this, the student concludes that the equation has one solution : 3 . a This equation has a second solution. Which one? b In their solution method, this student used R as the solution set rather than R . Explain why? 2 A student solves an inequality as follows : ( I ) : x + 1 x 2 x + 1 2 x 1 x The student concludes that the set of solutions is the interval [1 ; + [ a Give the domain of the algebraic expression x +1 x . b Show that 1 is a solution to the inequality. c What mistake did the student make? Implicitly, what solution set did he or she use? d Solve the inequality ( I ) using a sign table. Additional question: 3 Without using sign tables : a Assume that x is a strictly negative number; solve the inequality ( I ) . b Assume that x is a strictly positive number; solve the inequality ( I ) . c Use this to deduce and find the answer to question 3 . https://chingmath.fr chapExoCorrec/319 sacados/319 chapExoCorrec/318 sacados/318 chapExoCorrec/348 sacados/348 chapExoCorrec/317 sacados/317 chapExoCorrec/315 sacados/315 chapExoCorrec/470 sacados/470
0;600;800;400;20Image A0;360;640;160;04Image B0;770;890;630;45Image C 00.510.51Cf E.309 The shortest distance between two points is a straight line. This fact is expressed by the triangle inequality relating the distances between three points : for any points A , B , C in the plane, the following always holds : AB AC + CB (Passing through point C lengthens the path unless it lies on segment ) . We will construct an isosceles triangle DEF at F such that DE =5 . Let x = EF = DF 1 Be given. Can this triangle be constructed for x =2 ? 2 Give a range of possible values for x . 3 Express the value p of the perimeter of triangle DEF in terms of the value x . 4 For x satisfying the range : 2 ; 5 x 5 . Give the corresponding bounding rectangle for p . E.6755 A black-and-white digital image is made up of small squares (pixels) ranging in color from white through all shades of gray to black. Each shade is coded by a real x as follows : x =0 for white ; x =1 for black; x =0.01 ; x =0.02 and so on up to x =0.99 in steps of 0.01 for all intermediate shades (from light to dark) . The image A , below, is composed of four pixels and gives a sample of these shades with their codes. Image retouching software uses digital functions known as ˇ re-touching functions ı. A function f defined on the interval 0 ; 1 is said to ˇ function of retouche ı if it has the following four properties : f (0)=0 ; f (1)=1 ; f is continuous on the interval 0 ; 1 ; f is increasing on the interval 0 ; 1 . A shade coded x is said to be darkened by the function f if f ( x ) >x , and lightened, if f ( x ) <x . if f ( x )= x 2 , a pixel of coded shade 0.2 will take on the coded shade 0.2 2 =0.04 . Image A will be transformed into image B below. If f ( x )= x , the coded shade 0.2 will take on the coded shade 0.2 0.45 . The image A will be transformed into the image C below. Consider the function f defined on the interval 0 ; 1 by: f ( x ) = 4 x 3 6 x 2 + 3 x We admit that the function f is a touch-up function. Its representative curve C f is given below : 1 Graphically solve the inequation f ( x ) x , using the graph given below, showing the useful dotted lines. 2 Interpret this result in terms of lightening or darkening. https://chingmath.fr chapExoCorrec/309 sacados/309 chapExoCorrec/6755 sacados/6755 0;600;800;400;20Image A0;360;640;160;04Image B0;770;890;630;45Image C 00.510.51Cf
012345678910111213141524681012141618202224262830323436384042444648505254C nombre de pièces en milliers024681012141618202224262830milliers d’euros50100150200250300350400450500CR E.7005 The company BBE (Bio Bois Én-ergie) manufactures and sells wood pellets to fuel boilers and stoves in homes and communities. The company produces between 1 and 15 tons of pellets per day. Daily manufacturing costs are modeled by the function C defined on the interval 1 ; 15 by: C ( x ) = 0.3 · x 2 x + e x +5 x denotes the quantity of pellets in tons and C ( x ) the corresponding daily manufacturing cost in hundreds of euros. In the company BBE the selling price of one ton of wood pellets is 300 euros. The company’s daily revenue is therefore given by the function R defined on the interval 1 ; 15 by: R ( x ) = 3 · x x denotes the quantity of pellets in tons and R ( x ) the corresponding daily revenue in hundreds of euros. We define by D ( x ) the company’s daily net income in hundreds of euros, i.e. the difference between revenue R ( x ) and cost C ( x ) , x denotes the quantity of pellets in tons. On the graph below, we give C and Δ the respective graph-ical representations of the functions C and R in a frame of reference with origin O . The following questions will be answered using the graph, and with the precision permitted by it. No justification is required. 1 Determine the quantity of pellets in tons for which the company’s daily cost is minimal. 2 a Determine the values C (6) and R (6) then derive an estimate of of the daily net income in euros generated by the company for 6 tons of pellets manufactured and sold. b Determine the possible quantities of pellets in tons that the company must produce and sell daily to generate a positive net result, i.e. a profit. E.7055 A company produces and sells electronic components. Its monthly production capacity is between 1 000 and 30 000 pieces. It is assumed that all production is marketed. Given below are R and C the respective graphical representa-tions of the revenue and cost functions on the interval 1 ; 30 . By graphical reading, give an estimate of the values requested. 1 What is the production cost of 21 000 pieces? 2 For what quantities of parts produced, does the company make a profit? 3 For what number of pieces produced is the profit maxi-mum? https://chingmath.fr chapExoCorrec/7005 sacados/7005 012345678910111213141524681012141618202224262830323436384042444648505254C chapExoCorrec/7055 sacados/7055 nombre de pièces en milliers024681012141618202224262830milliers d’euros50100150200250300350400450500CR
nombre de jours01020304050607080milliers d’habitants24681012 E.7060 The population evolution of a sea-side resort for the summer 2015 was modeled by a function f , defined on the interval 0 ; 70 , whose representative curve is given below. Where x is the number of days after 1 er July, f ( x ) denotes the population in thousands. Thus, x =30 corresponds to 31 July and f (30) represents the population expected to be accommodated on 31 July. It is estimated that one inhabitant will use between 45 and 55 liters of water per day. The answers to the following questions are to be provided by graphical reading. 1 a Estimate the maximum number of inhabitants present in the seaside resort according to this model during the summer 2015 and specify when this maxi-mum would be reached. b The commune is able to supply 600 000 liters of water per day, is this enough? 2 Estimate the number of days on which the number of in-habitants of the resort is expected to remain above 80 % of the maximum number expected. E.5661 Complete the table below : a b Compare a and b Sign of b a 5 3 2.7 4 3 7 5 7 4 3 5 6 4 ı E.6429 1 Give the sign of each of the following calculations : a 5 3 b 2.4 ( 3.2) c 3.6 7.9 d 2 3 5 6 e 6 14 9 21 f 3 ı 2 Deduce from the previous question the comparison of the following numbers : a 5 : : : 3 b 2.4 : : : 3.2 c 3.6 : : : 7.9 d 2 3 : : : 5 6 e 6 14 : : : 9 21 f 3 : : : ı https://chingmath.fr chapExoCorrec/7060 sacados/7060 Extrait Antilles-Guyane Septembre 2015 nombre de jours01020304050607080milliers d’habitants24681012 chapExoCorrec/5661 sacados/5661 chapExoCorrec/6429 sacados/6429