Question

find the sum of first 8 term of sequence 3 9 27​

Answer 1

Question :-

Find the sum of first 8 term of sequence 3,9,27...

Answer :-

Given :-

a = 3

d = 6

n = 8

Putting the value in Formula

$s_{n} = \frac{n}{2} [ 2a(n - 1)d]$

$= \frac{8}{2} [ 2(3)(8 - 1)6]$

$= 4[ 6(7)6]$

$= 4[252 ]$

$= 1008$

Therefore the sum of 8 term of given A.P is 1008

Answer 2

Answer :-

Given :-

a = 3

d = 6

n = 8

Putting the value in Formula

s_{n} = \frac{n}{2} [ 2a(n - 1)d]s

n

=

2

n

[2a(n−1)d]

= \frac{8}{2} [ 2(3)(8 - 1)6]=

2

8

[2(3)(8−1)6]

= 4[ 6(7)6]=4[6(7)6]

= 4[252 ]=4[252]

= 1008=1008

Therefore the sum of 8 term of given A.P is 1008