Question

A6-Sequences and Series

Q1. Below are the first few terms of some important mathematical sequences. State the 7th term
of each sequence:
a) 2, 4, 6, 8, .......
b) 1, 4, 9, 16, ....
c) 1, 8, 27, 64, ....
d) 2, 3, 5, 7, 11, ....


7th term is.
7th term
7th term is .............. (1)
7th term is ........…….…….. (1)
(Total 4 marks)

Answer 1

Explanation:

7th term of the first sequence is 14

first we need to find out the nth term so,

tn=Ti+(n-1)d

2(n-1)2

2+2n-2

2n+2-2

2n+0

Now we need to find out the 7th term

n=7

2(7)-0

14-0=0

Second sequences 7th term is 33

first we need to find the nth term

1(n-1)3

1+3n-3

3n+1-3

3n-2

so now we need to find 7th term

3(7)-2

35-3

33

the 4th sequence 7th term is 20