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 = 8+a1 and an = 2an-1 + 7 for n > 2


Answer:_______________




2)  

 Find the first five terms of the sequence given by 

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


Answer:_______________




3)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 9+a1 and an = 2an-1 + 6 for n > 2


Answer:_______________




4)  

 Find the first five terms of the sequence given by 

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


Answer:_______________




5)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 3+a1 and an = 2an-1 + 4 for n > 2


Answer:_______________




6)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 12+a1 and an = 2an-1 + 4 for n > 2


Answer:_______________




7)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 7 for n > 2


Answer:_______________




8)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 11+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 + 6 for n > 2


Answer:_______________




10)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 13+a1 and an = 2an-1 + 8 for n > 2


Answer:_______________




 

1)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 8+a1 and an = 2an-1 + 7 for n > 2

Answer: 2,10,27,61,129


SOLUTION 1 :

 Given a1 = 2, a2 = 8 + a1 and  an = 2an-1+7

a1 = 2 . a2 = 8 + 2 = 10

For n = 3, 

a3 = 2a3-1 + 7

= 2a2 + 7

= 2(10) + 7 = 27

For 4

= a4 = 2a4-1 + 7

= 2a3 + 7

= 2(27) + 7 = 61

 For 5

 = a5 = 2a5-1 + 7

= 2a4 + 7

= 2(61) + 7 = 129

Hence the first five terms of the sequence are 2,10,27,61,129.



2)  

 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.



3)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 9+a1 and an = 2an-1 + 6 for n > 2

Answer: 2,11,28,62,130


SOLUTION 1 :

 Given a1 = 2, a2 = 9 + a1 and  an = 2an-1+6

a1 = 2 . a2 = 9 + 2 = 11

For n = 3, 

a3 = 2a3-1 + 6

= 2a2 + 6

= 2(11) + 6 = 28

For 4

= a4 = 2a4-1 + 6

= 2a3 + 6

= 2(28) + 6 = 62

 For 5

 = a5 = 2a5-1 + 6

= 2a4 + 6

= 2(62) + 6 = 130

Hence the first five terms of the sequence are 2,11,28,62,130.



4)  

 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.



5)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 3+a1 and an = 2an-1 + 4 for n > 2

Answer: 2,5,14,32,68


SOLUTION 1 :

 Given a1 = 2, a2 = 3 + a1 and  an = 2an-1+4

a1 = 2 . a2 = 3 + 2 = 5

For n = 3, 

a3 = 2a3-1 + 4

= 2a2 + 4

= 2(5) + 4 = 14

For 4

= a4 = 2a4-1 + 4

= 2a3 + 4

= 2(14) + 4 = 32

 For 5

 = a5 = 2a5-1 + 4

= 2a4 + 4

= 2(32) + 4 = 68

Hence the first five terms of the sequence are 2,5,14,32,68.



6)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 12+a1 and an = 2an-1 + 4 for n > 2

Answer: 2,14,32,68,140


SOLUTION 1 :

 Given a1 = 2, a2 = 12 + a1 and  an = 2an-1+4

a1 = 2 . a2 = 12 + 2 = 14

For n = 3, 

a3 = 2a3-1 + 4

= 2a2 + 4

= 2(14) + 4 = 32

For 4

= a4 = 2a4-1 + 4

= 2a3 + 4

= 2(32) + 4 = 68

 For 5

 = a5 = 2a5-1 + 4

= 2a4 + 4

= 2(68) + 4 = 140

Hence the first five terms of the sequence are 2,14,32,68,140.



7)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 6+a1 and an = 2an-1 + 7 for n > 2

Answer: 2,8,23,53,113


SOLUTION 1 :

 Given a1 = 2, a2 = 6 + a1 and  an = 2an-1+7

a1 = 2 . a2 = 6 + 2 = 8

For n = 3, 

a3 = 2a3-1 + 7

= 2a2 + 7

= 2(8) + 7 = 23

For 4

= a4 = 2a4-1 + 7

= 2a3 + 7

= 2(23) + 7 = 53

 For 5

 = a5 = 2a5-1 + 7

= 2a4 + 7

= 2(53) + 7 = 113

Hence the first five terms of the sequence are 2,8,23,53,113.



8)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 11+a1 and an = 2an-1 + 7 for n > 2

Answer: 2,13,33,73,153


SOLUTION 1 :

 Given a1 = 2, a2 = 11 + a1 and  an = 2an-1+7

a1 = 2 . a2 = 11 + 2 = 13

For n = 3, 

a3 = 2a3-1 + 7

= 2a2 + 7

= 2(13) + 7 = 33

For 4

= a4 = 2a4-1 + 7

= 2a3 + 7

= 2(33) + 7 = 73

 For 5

 = a5 = 2a5-1 + 7

= 2a4 + 7

= 2(73) + 7 = 153

Hence the first five terms of the sequence are 2,13,33,73,153.



9)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 12+a1 and an = 2an-1 + 6 for n > 2

Answer: 2,14,34,74,154


SOLUTION 1 :

 Given a1 = 2, a2 = 12 + a1 and  an = 2an-1+6

a1 = 2 . a2 = 12 + 2 = 14

For n = 3, 

a3 = 2a3-1 + 6

= 2a2 + 6

= 2(14) + 6 = 34

For 4

= a4 = 2a4-1 + 6

= 2a3 + 6

= 2(34) + 6 = 74

 For 5

 = a5 = 2a5-1 + 6

= 2a4 + 6

= 2(74) + 6 = 154

Hence the first five terms of the sequence are 2,14,34,74,154.



10)  

 Find the first five terms of the sequence given by 

a1 = 2, a2 = 13+a1 and an = 2an-1 + 8 for n > 2

Answer: 2,15,38,84,176


SOLUTION 1 :

 Given a1 = 2, a2 = 13 + a1 and  an = 2an-1+8

a1 = 2 . a2 = 13 + 2 = 15

For n = 3, 

a3 = 2a3-1 + 8

= 2a2 + 8

= 2(15) + 8 = 38

For 4

= a4 = 2a4-1 + 8

= 2a3 + 8

= 2(38) + 8 = 84

 For 5

 = a5 = 2a5-1 + 8

= 2a4 + 8

= 2(84) + 8 = 176

Hence the first five terms of the sequence are 2,15,38,84,176.