Question

Find the 7th and nth term of the GP 0.4, 0.8, 1.6...​

Answer 1

Given:—

GP is 0.4, 0.8, 1.6….

The given GP is of the form, a, ar, ar2, ar3….

Where r is the common ratio.

→ First term in the given GP, a1 = a = 0.4

→ Second term in GP, a2 = 0.8

Now, the common ratio,

r = a2/a1

r = 0.8/0.4

Now,

nth term of GP is, an = arn – 1

So,

the 7th term in the GP,

a7 = ar6

= 0.4 x 26

= 25.6

nth term in the GP,

an = arn – 1

= (0.4)(2) n – 1

= (0.2)2n

Hence,

7th term = 25.6 and nth term = (0.2)2n