Outside the high school program / Sequences 39 exercises (including 38 corrected)

a
1erétape2ièmeétape3ièmeétape 1erétape2eétape3eétape 1. Any sequences E.7716 For each question, determine the first four terms of the sequence u n n N : a u n = n + 1 n + 2 b u n +1 = 2 · u n 2 ; u 0 = 3 c u n = n 2 + n + 1 d u n +1 = 2 · u n 2 ; u 0 = 1 e u n = n 2 n + 1 f u n +1 = u n 2 u n + 1 ; u 0 = 2 E.4556 Consider the construction of a house of cards : For any non-zero natural number ( n N ) , we note u n the number of cards needed to build the n ème step. Thus, we have : u 1 = 2 ; u 2 = : : : ; u 3 = : : : ; u 4 = : : : E.7498 The figures below are constructed using small wooden sticks. For n a strictly positive integer ( n N ) , , we denote u n the number of sticks needed for construction in step n . We there-fore have : u 1 = 10 ; u 2 = : : : ; u 3 = : : : ; u 4 = : : : E.7598 Consider the sequence u n defined for any integer n positive or zero ( n N ) by: u 0 = 2 ; u n +1 = u n + n n + 1 Determine the first four terms of the sequence u n . E.7492 Consider the following sequences of num-bers : a a 0 =4 ; a 1 =7 ; a 2 =10 ; a 3 =13 ; a 4 =16 . . . b b 0 =1 ; b 1 = 2 ; b 2 =4 ; b 3 = 8 ; b 4 =16 . . . c c 0 =1 ; c 1 =3 ; c 2 =5 ; c 3 =7 ; c 4 =9 . . . d d 0 =16 ; d 1 =8 ; d 2 =4 ; d 3 =2 ; d 4 =1 . . . Associate each of these sequences with one of the following relations, which defines the value of a term either in terms of the value of its predecessor or in terms of its rank: 1 u n +1 = u n + 2 2 u n = 4 + 3 · n 3 u n +1 = 2 · u n 4 u n = 16 × 1 2 n E.4557 1 Here are some examples of number sequences : a ( 2 ; 5 ; 8 ; 11 ; 14 ; : : : ) b ( 2 ; 6 ; 18 ; 54 ; 162 ; : : : ) c ( 6 ; 6 ; 6 ; 6 ; 6 ; : : : ) d ( 1 ; 3 ; 7 ; 15 ; 31 ; : : : ) For each of these number sequences, find the relationship that allows you to obtain a value based on the previous values. 2 Here are some other examples of number sequences : a ( 0 ; 2 ; 4 ; 6 ; 8 ; : : : ) b ( 1 ; 6 ; 11 ; 16 ; 21 ; : : : ) c ( 1 ; 2 ; 4 ; 8 ; 16 ; 32 ; : : : ) d ( 1 ; 2 ; 3 ; 2 ; 5 ; 6 ; : : : ) e 2 ; 3 2 ; 4 3 ; 5 4 ; 6 5 ; : : : For each of these sequences of numbers, find the rela-tionship that allows you to obtain a value based on its position in the sequence. E.4559 Consider the sequences defined below by the value of their first term and a recurrence relation where the integer n denotes a positive or zero integer ( n N ) : a u 0 = 5 ; u n +1 = u n + 2 b v 0 = 3 ; v n +1 = 2 · v n c w 0 = 2 ; w n +1 = w n d x 0 = 4 ; x n +1 = 2 · x n 2 d y 0 = 1 ; y 1 = 1 ; y n +1 = y n + y n 1 Determine the first five terms of each of these sequences. https://chingmath.fr chapExoCorrec/7716 sacados/7716 chapExoCorrec/4556 sacados/4556 1erétape2ièmeétape3ièmeétape chapExoCorrec/7498 sacados/7498 1erétape2eétape3eétape chapExoCorrec/7598 sacados/7598 chapExoCorrec/7492 sacados/7492 chapExoCorrec/4557 sacados/4557 chapExoCorrec/4559 sacados/4559
n01020304050un-2-11234 -4-3-2-1234I-3-2-1234JOCf E.4581 For each question, a sequence is defined where the rank n denotes a positive integer or zero ( n N ) . Determine the first five terms of the sequence u n : a u n = n + 1 n + 2 b u n +1 = 2 · u n 2 ; u 0 = 3 c u n = n 2 + n + 1 d u n +1 = 2 · u n 2 ; u 0 = 1 e u n = n 2 n + 1 f u n +1 = u n 2 u n + 1 ; u 0 = 2 E.4604 1 Consider the sequence u n whose rank term n , a posi-tive or zero integer, is given by the relation: u n = 7 4 · 1 ( 1) n + 3 a Determine the first five terms of this sequence. b What can be said about the value of the terms in the sequence u n ? 2 Consider the sequence v n defined, for any positive or zero rank, by: v n +1 = 1 v n 1 + v n ; v 0 = 3 a Determine the first five terms of the sequence v n . b What do we notice? E.7539 Consider the two algorithms below : Algorithm 1 u 4 For i ranging from 1 to 53 u u + 3 End For Algorithm 2 u 1 For i ranging from 1 to 4 u 2 × u + 1 End For For each algorithm, give the value contained in variable u after the algorithm has been executed. E.7591 1 Determine the first four terms of the sequence u n de-fined for any positive or zero integer ( n N ) : u 0 =3 ; u n +1 =2 · u n 2 2 Determine the first four terms of the sequence v n de-fined for any positive or zero integer ( n N ) : v n = n + 1 2 · n + 1 E.7597 Consider the sequence u n defined for any integer n positive or zero ( n N ) by: u 0 = 3 ; u n +1 = 2 · u n + 1 n + 1 Determine the first four terms of the sequence u n . E.7592 1 Determine the first four terms of the sequence u n de-fined for any positive or zero integer ( n N ) : u 0 =4 ; u n +1 =3 2 · u n 2 Determine the first four terms of the sequence v n de-fined for any positive or zero integer ( n N ) : v n = 2 · n 1 n + 3 E.4558 Consider the numerical sequences de-fined below, where their rank n is a positive integer or zero ( n N ) : a u n = 2 n b v n = 3 n 4 c w n = n 2 + 3 d x n = 2 n Determine the first five terms of each of these sequences. 2. Any sequences and graphical reading E.7750 Consider a sequence u n defined for any natural number n positive or zero ( n N ) . In a reference frame are represented the points with coordinates ( n ; u n ) for n between 0 and 50 : 1 Give the exact values of u 0 and u 10 . 2 Give approximate values of u 5 , u 30 and u 40 . 3 What can be said about the values of the terms u n as the value of n increases? E.4584 In the plane provided with an orthonor-mal reference frame O ; I ; J , consider the representation C f of a function f defined on the interval [ 4 ; 4] : Consider the sequences ( u n ) n N and ( v n ) n N verifying the re- https://chingmath.fr chapExoCorrec/4581 sacados/4581 chapExoCorrec/4604 sacados/4604 chapExoCorrec/7539 sacados/7539 chapExoCorrec/7591 sacados/7591 chapExoCorrec/7597 sacados/7597 chapExoCorrec/7592 sacados/7592 chapExoCorrec/4558 sacados/4558 chapExoCorrec/7750 sacados/7750 n01020304050un-2-11234 chapExoCorrec/4584 sacados/4584 -4-3-2-1234I-3-2-1234JOCf
-4-3-2-1234I-4-3-2-1234JOCf -2-123456I-1234567JOCf -12345678I-1234JOCf lations : u n +1 = f u n ; v n +1 = f v n verifying the following initial conditions : u 0 = 1 ; v 0 = 4 Determine the first 100 terms of each of these two sequences. E.4583 Consider the function f defined on [ 4 ; 4] dont representative curve C f est given below : Consider the sequence u n n N defined by the relation u 0 = 2 and u n +1 = f u n . 1 Show that the term u 1 est equals 3 . 2 Justify the following equalities: a u 2 = 0.5 b u 3 = 2.5 3 Complete the following table : n 0 1 2 3 4 5 6 7 8 9 u n E.4610 In the plane provided with a O ; I ; J orthonormal, consider the curve C f representative of the func-tion f defined by the relation: f ( x ) = 12 x + 36 x 24 The line (Δ) is the first bisector of the plane. Consider the sequence u n n N defined by recurrence by: u n +1 = f u n ; u 0 = 2 1 Graphically, place on the x-axis the first five values of the sequence u n . 2 Determine, by calculation, the value of the first three terms of the sequence u n . E.4609 In the plane provided with a O ; I ; J orthonormal, consider the curve C f of the function f whose image of a number x is defined by: f ( x ) = x + 4 x + 2 The line (Δ) is the first bisector of the plane. Consider the sequence u n n N defined by the relation: u n +1 = f u n ; u 0 = 8 1 On the x-axis, show the values of the first six terms of the sequence. 2 Determine, by calculation, the first three terms of the sequence u n . https://chingmath.fr chapExoCorrec/4583 sacados/4583 -4-3-2-1234I-4-3-2-1234JOCf chapExoCorrec/4610 sacados/4610 -2-123456I-1234567JOCf chapExoCorrec/4609 sacados/4609 -12345678I-1234JOCf
3. Sum of terms E.7724 1 Consider the arithmetic sequence u n with first term 4 and reason 2 3 a Determine the first three terms of the sequence u n . b Determine the rank of the sequence u n having value 38 . c Determine the sum of terms : S = u 0 + u 1 + · · · + u 99 . 2 Consider the geometric sequence v n of first term 4 and reason 2 3 a Determine the first three terms of the sequence v n . b Determine the sum of the terms : S = v 0 + v 1 + · · · + v 15 . E.7798 1 Consider the arithmetic sequence u n with first term 1 3 and reason 1 2 a Determine the first three terms of the sequence u n . b Determine the rank of the term u n having value 77 6 . c Determine the sum of terms : S = u 0 + u 1 + · · · + u 99 . 2 Consider the geometric sequence v n of first term 1 3 and reason 1 2 a Determine the first three terms of the sequence v n . b Determine the sum of the terms : S = v 0 + v 1 + · · · + v 15 . E.6547 1 Consider the suite u n n N arithmetic with first term 5 and reason 3 . Determine the value of the sum S of the 100 first terms of this sequence. 2 Consider the geometric sequence v n n N of first term 3 and reason 1 4 . Determine the value of the sum S of the first 100 terms of this sequence. E.2453 1 Let u n ) n N be an arithmetic sequence of first term 2 and reason 3 5 , determine the value of the following sum : S = u 5 + u 6 + · · · + u 21 2 Consider the following sum whose terms are those of a geometric sequence : S = 16 + 24 + 36 + · · · + 3 10 2 6 Determine the value of the sum S . E.5172 Consider the sequence u n defined by: u 0 = 0 ; u n +1 = 1 2 · u n + 1 for all n N 1 Determine the first five terms of the sequence u n . 2 Consider the sequence v n defined by: v n = u n 2 3 for all n N a Determine the first four terms of the sequence v n . b Establish that for any natural number n , we have : v n +1 = 1 2 · v n c Give the nature and values of the characteristic ele-ments of the sequence v n . 3 a Determine the value of the sum S defined by: S = v 0 + v 1 + · · · + v 14 b Determine the value of the sum S defined by: S = u 0 + u 1 + · · · + u 14 4 a Give the expression of the term v n as a function of its rank n . b Give the expression of the term u n as a function of its rank n . E.3017 1 Consider a sequence u n n N arithmetic such that : u 13 = 7 ; u 20 = 35 2 a Justifying your approach, find the characteristic ele-ments of this sequence. b Deduce the value of the sum S defined by: S = u 5 + u 6 + · · · + u 22 2 Consider a geometric sequence v n n N such that : v 9 = 5 6 7 4 ; v 16 = 5 13 7 11 a Justifying your approach, find the characteristic ele-ments of this sequence. b Deduce the value of the sum S defined by: S = v 5 + v 6 + · · · + v 22 E.7607 1 Consider the sequence u n geometric with first term 2 and reason 3 . Determine the sum of the first 10 terms of the sequence u n . 2 Consider the sequence v n geometric of first term 5 and reason 1 2 . Determine an expression for the sum S defined by: S = v 0 + v 1 + v 2 + · · · + v 12 Then give the value of S rounded to the nearest hun-dredth. https://chingmath.fr chapExoCorrec/7724 sacados/7724 Merci Tofeil! 1s2 chapExoCorrec/7798 sacados/7798 chapExoCorrec/6547 sacados/6547 chapExoCorrec/2453 sacados/2453 chapExoCorrec/5172 sacados/5172 chapExoCorrec/3017 sacados/3017 chapExoCorrec/7607 sacados/7607
1erétape2ièmeétape3ièmeétape E.8471 The terms of each sum are the terms of a geometric sequence. Determine the value of these two sums : 1 S 1 = 1 + 1 2 + 1 4 + 1 8 + · · · + 1 1024 2 S 2 = 2 + 3 + 3 2 + 3 3 4 + 9 8 E.8467 Consider the sum S defined by: S = 5 + 2 1 4 · · · 37 Deduce the value of S . E.7663 Consider the sum S defined by: S = 1 + 5 2 + 4 + 11 2 + · · · + 100 We admit that the terms of the sum S are the first successive terms of a sequence u n arithmetic defined on N . 1 Donner les éléments caractéristiques de la suite u n et déterminer le rang du terme de la suite ayant 100 pour valeur. 2 Deduce the value of the sum S . 4. Course - old program: Suites E.3291 The following results are assumed to be known : Definition-proposition: (1) two sequences ( u n ) and ( v n ) are said to be adjacent when : one is increasing, the other is decreasing, and u n v n tends toward 0 as n tends toward + ; (2) if ( u n ) and ( v n ) are two adjacent sequences such that ( u n ) is increasing and ( v n ) is decreasing, then for any n belonging to N , we have : u n v n ; (3) any increasing and bounded sequence is convergent ; any decreasing and bounded sequence is convergent. Then prove the following proposition : ˇ Two adjacent sequences are convergent and have the same limit ı. E.3445 Consider the three sequences u n n N , v n n N , w n n N which verify the following conditions : The two sequences v n and w n converge to a real num-ber . From a rank n 0 and for any integer n greater than n 0 , we have : vCOPY 06 u n w n Show that the sequence u n is convergent and, more pre-cisely, has the following limit: lim n ↦→ + u n = E.3475 Using the definition and the two properties below, show that if u n and v n are two adjacent sequences, then they are convergent and have the same limit. Definition: Two sequences are adjacent when one is increasing, the other is decreasing and the difference of the two con-verges to 0 . Property 1: If two sequences u n and v n are adjacent with u n increasing and v n decreasing then for any natural number: u n v n . Property 2: any increasing and majoring sequence converges ; any decreasing and minoring sequence converges. 5. Recalls on suites E.6124 Consider the construction of a house of cards : How many cards are needed to complete the 4 ième stage of this construction? for the 5 ième stage? https://chingmath.fr chapExoCorrec/8471 sacados/8471 chapExoCorrec/8467 sacados/8467 chapExoCorrec/7663 sacados/7663 chapExoCorrec/3291 sacados/3291 Extrait France Juin 2005 chapExoCorrec/3445 sacados/3445 chapExoCorrec/3475 sacados/3475 chapExoCorrec/6124 sacados/6124 1erétape2ièmeétape3ièmeétape
1erétape2ièmeétape3ièmeétape un1ununun un1ununun un1ununun un1ununun 0,20,40,60,8I0,20,40,60,8JOu0u1f(u0 E.6144 Consider the following constructions : Note u n the numerical sequence defined on N where u n represents the number of matches required to construct the n ième step. Which of the following definitions can be used to define the sequence u n shown above : a u 1 = 4 u n +1 = 4 · u n b u 1 = 4 u n +1 = u n + 4 · n c u 1 = 4 u n +1 = u n + 4 · ( n + 1) d u 1 = 4 u n +1 = 4 · u n + n E.6125 Consider the numerical sequences, be-low, defined on N by recurrence : i.e. according to their initial value and a relationship with the preceding terms. 1 u 0 =5 ; u n +1 = u n +2 for all n N . 2 v 0 =3 ; v n +1 =2 · v n for any n N . 3 w 0 =2 ; w n +1 = w n for any n N . 4 x 0 =4 ; x n +1 =2 · x n 2 for any n N 5 x 0 =1 ; x 1 =1 ; x n +1 = x n + x n 1 for all n N Determine the first five terms of each of these sequences. 6. Unclassified financial years E.4644 Consider the sequence u n defined on N by the following recurrence relation: u 0 = 0 ; u n +1 = u n 2 n + 11 1 a Using the software of your choice, plot the scatter-plot associated with the first 15 terms of this sequence. b Make a conjecture as to the nature of the curve passing through these points. 2 a Determine the function f defined by a polynomial of the second degree, verifying the relations : u 0 = f (0) ; u 1 = f (1) ; u 11 = f (11) b Give the reduced expression of the expression : f ( x +1) f ( x ) . c Establish the expression of the terms of the sequence u n as a function of their rank n . E.5105 Consider the sequence u n defined by: u 0 = 1 ; u n +1 = 1 2 · u n + 1 for all n N 1 Determine the first four terms of this sequence. 2 a Establish the following equality for all n N : u n +2 = 1 4 · u n + 1 2 b Establish the following equality for all n N : u n +2 = u n + u n +1 2 3 When representing four terms of the sequence u n on a graduated line, which of the four propositions below would best represent them? a b c d E.6635 Consider the function f defined on 0 ; 1 by the relation: f ( x ) = 5 4 1 x + 1 1 a Establish the following values : f 1 4 = 9 20 ; f f 1 4 = 65 116 b Determine the value of : f f f 1 4 Below is the representative curve C f of the function f in the orthonormal coordinate system O ; I ; J : 2 a Give the values rounded to the nearest thousandth of the following numbers : u 0 = 1 4 = : : : : : : u 1 = 9 20 : : : : : : u 2 = 65 116 : : : : : : u 3 = 441 724 : : : : : : b Place the values u 2 and u 3 on the x-axis. https://chingmath.fr chapExoCorrec/6144 sacados/6144 1erétape2ièmeétape3ièmeétape chapExoCorrec/6125 sacados/6125 sacados/4644 chapExoCorrec/5105 sacados/5105 un1ununun un1ununun un1ununun un1ununun chapExoCorrec/6635 sacados/6635 0,20,40,60,8I0,20,40,60,8JOu0u1f(u0
c Place the values f ( u 1 ) , f ( u 2 ) , and f ( u 3 ) on the y-axis. 3 a Draw the line segment connecting the two points A 1 ( u 1 ; 0) and B 1 (0 ; f ( u 0 )) . What is the nature of triangle OA 1 B 1 ? b For i ranging from 1 to 3 , we define the points : A i ( u i ; 0) and B i 0 ; f u i 1 What are the natures of the triangles OA i B i ? c Place the numbers u 4 and u 5 on the x-axis defined by the relations : f ( u 3 ) = u 4 ; f ( u 4 ) = u 5 4 Generation of the terms of the sequence : a Enter and execute this program in the programming language of your choice. x 0.25 For i ranging from 0 to 100 x 5 4 1 x + 1 End For At the end of execution, what is the value of the vari-able x ? b What conjecture can be made about the terms of this sequence? E.5107 Consider the sequence u n n N defined by: u 0 = 5 ; u n = 1 + 2 n · u n 1 + 6 n pour n N . 1 a Complete the following table : n 0 1 2 3 4 5 6 u n b Make a conjecture about the nature of the sequence d n defined by: d n = u n +1 u n 2 We consider the sequence v n defined by: v n = 4 n 2 + 12 n + 5 for all n N a Give the simplified expression of the expression v n +1 as a function of n . b Simplify the expression of : 1+ 2 n +1 · v n + 6 n +1 . (We’ll use the factorization : 4 x 3 + 24 x 2 + 41 x + 21 = ( x + 1)(4 x 2 + 20 x + 21) ) c What can we say about the sequences u n et v n . https://chingmath.fr chapExoCorrec/5107 sacados/5107