Scroll:Sequences and series >> Worked Examples >> saq (4219)


Written Instructions:

For each Multiple Choice Question (MCQ), four options are given. One of them is the correct answer. Make your choice (1,2,3 or 4). Write your answers in the brackets provided..

For each Short Answer Question(SAQ) and Long Answer Question(LAQ), write your answers in the blanks provided.

Leave your answers in the simplest form or correct to two decimal places.



 

1)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 8 for n > 2


Answer:_______________




2)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 7+a1 and an = 2an-1 + 5 for n > 2


Answer:_______________




3)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 3+a1 and an = 2an-1 + 5 for n > 2


Answer:_______________




4)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 4 for n > 2


Answer:_______________




5)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 5+a1 and an = 2an-1 + 6 for n > 2


Answer:_______________




6)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 15+a1 and an = 2an-1 + 4 for n > 2


Answer:_______________




7)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 4+a1 and an = 2an-1 + 5 for n > 2


Answer:_______________




8)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 9+a1 and an = 2an-1 + 7 for n > 2


Answer:_______________




9)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 12+a1 and an = 2an-1 + 8 for n > 2


Answer:_______________




10)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 6 for n > 2


Answer:_______________




 

1)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 8 for n > 2

Answer: 2,8,24,56,120


SOLUTION 1 :

 Given a1 = 2, a2 = 6 + a1 and  an = 2an-1+8

a1 = 2 . a2 = 6 + 2 = 8

For n = 3, 

a3 = 2a3-1 + 8

= 2a2 + 8

= 2(8) + 8 = 24

For 4

= a4 = 2a4-1 + 8

= 2a3 + 8

= 2(24) + 8 = 56

 For 5

 = a5 = 2a5-1 + 8

= 2a4 + 8

= 2(56) + 8 = 120

Hence the first five terms of the sequence are 2,8,24,56,120.



2)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 7+a1 and an = 2an-1 + 5 for n > 2

Answer: 2,9,23,51,107


SOLUTION 1 :

 Given a1 = 2, a2 = 7 + a1 and  an = 2an-1+5

a1 = 2 . a2 = 7 + 2 = 9

For n = 3, 

a3 = 2a3-1 + 5

= 2a2 + 5

= 2(9) + 5 = 23

For 4

= a4 = 2a4-1 + 5

= 2a3 + 5

= 2(23) + 5 = 51

 For 5

 = a5 = 2a5-1 + 5

= 2a4 + 5

= 2(51) + 5 = 107

Hence the first five terms of the sequence are 2,9,23,51,107.



3)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 3+a1 and an = 2an-1 + 5 for n > 2

Answer: 2,5,15,35,75


SOLUTION 1 :

 Given a1 = 2, a2 = 3 + a1 and  an = 2an-1+5

a1 = 2 . a2 = 3 + 2 = 5

For n = 3, 

a3 = 2a3-1 + 5

= 2a2 + 5

= 2(5) + 5 = 15

For 4

= a4 = 2a4-1 + 5

= 2a3 + 5

= 2(15) + 5 = 35

 For 5

 = a5 = 2a5-1 + 5

= 2a4 + 5

= 2(35) + 5 = 75

Hence the first five terms of the sequence are 2,5,15,35,75.



4)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 4 for n > 2

Answer: 2,8,20,44,92


SOLUTION 1 :

 Given a1 = 2, a2 = 6 + a1 and  an = 2an-1+4

a1 = 2 . a2 = 6 + 2 = 8

For n = 3, 

a3 = 2a3-1 + 4

= 2a2 + 4

= 2(8) + 4 = 20

For 4

= a4 = 2a4-1 + 4

= 2a3 + 4

= 2(20) + 4 = 44

 For 5

 = a5 = 2a5-1 + 4

= 2a4 + 4

= 2(44) + 4 = 92

Hence the first five terms of the sequence are 2,8,20,44,92.



5)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 5+a1 and an = 2an-1 + 6 for n > 2

Answer: 2,7,20,46,98


SOLUTION 1 :

 Given a1 = 2, a2 = 5 + a1 and  an = 2an-1+6

a1 = 2 . a2 = 5 + 2 = 7

For n = 3, 

a3 = 2a3-1 + 6

= 2a2 + 6

= 2(7) + 6 = 20

For 4

= a4 = 2a4-1 + 6

= 2a3 + 6

= 2(20) + 6 = 46

 For 5

 = a5 = 2a5-1 + 6

= 2a4 + 6

= 2(46) + 6 = 98

Hence the first five terms of the sequence are 2,7,20,46,98.



6)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 15+a1 and an = 2an-1 + 4 for n > 2

Answer: 2,17,38,80,164


SOLUTION 1 :

 Given a1 = 2, a2 = 15 + a1 and  an = 2an-1+4

a1 = 2 . a2 = 15 + 2 = 17

For n = 3, 

a3 = 2a3-1 + 4

= 2a2 + 4

= 2(17) + 4 = 38

For 4

= a4 = 2a4-1 + 4

= 2a3 + 4

= 2(38) + 4 = 80

 For 5

 = a5 = 2a5-1 + 4

= 2a4 + 4

= 2(80) + 4 = 164

Hence the first five terms of the sequence are 2,17,38,80,164.



7)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 4+a1 and an = 2an-1 + 5 for n > 2

Answer: 2,6,17,39,83


SOLUTION 1 :

 Given a1 = 2, a2 = 4 + a1 and  an = 2an-1+5

a1 = 2 . a2 = 4 + 2 = 6

For n = 3, 

a3 = 2a3-1 + 5

= 2a2 + 5

= 2(6) + 5 = 17

For 4

= a4 = 2a4-1 + 5

= 2a3 + 5

= 2(17) + 5 = 39

 For 5

 = a5 = 2a5-1 + 5

= 2a4 + 5

= 2(39) + 5 = 83

Hence the first five terms of the sequence are 2,6,17,39,83.



8)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 9+a1 and an = 2an-1 + 7 for n > 2

Answer: 2,11,29,65,137


SOLUTION 1 :

 Given a1 = 2, a2 = 9 + a1 and  an = 2an-1+7

a1 = 2 . a2 = 9 + 2 = 11

For n = 3, 

a3 = 2a3-1 + 7

= 2a2 + 7

= 2(11) + 7 = 29

For 4

= a4 = 2a4-1 + 7

= 2a3 + 7

= 2(29) + 7 = 65

 For 5

 = a5 = 2a5-1 + 7

= 2a4 + 7

= 2(65) + 7 = 137

Hence the first five terms of the sequence are 2,11,29,65,137.



9)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 12+a1 and an = 2an-1 + 8 for n > 2

Answer: 2,14,36,80,168


SOLUTION 1 :

 Given a1 = 2, a2 = 12 + a1 and  an = 2an-1+8

a1 = 2 . a2 = 12 + 2 = 14

For n = 3, 

a3 = 2a3-1 + 8

= 2a2 + 8

= 2(14) + 8 = 36

For 4

= a4 = 2a4-1 + 8

= 2a3 + 8

= 2(36) + 8 = 80

 For 5

 = a5 = 2a5-1 + 8

= 2a4 + 8

= 2(80) + 8 = 168

Hence the first five terms of the sequence are 2,14,36,80,168.



10)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 6 for n > 2

Answer: 2,8,22,50,106


SOLUTION 1 :

 Given a1 = 2, a2 = 6 + a1 and  an = 2an-1+6

a1 = 2 . a2 = 6 + 2 = 8

For n = 3, 

a3 = 2a3-1 + 6

= 2a2 + 6

= 2(8) + 6 = 22

For 4

= a4 = 2a4-1 + 6

= 2a3 + 6

= 2(22) + 6 = 50

 For 5

 = a5 = 2a5-1 + 6

= 2a4 + 6

= 2(50) + 6 = 106

Hence the first five terms of the sequence are 2,8,22,50,106.