Question

fourth term of a G.p is 40 and the tenth
term is 2560 find the seventh term.​

Answer 1

Answer:

answr

search

What would you like to ask?

11th

Maths

Sequences and Series

General Term of a G.P

The fourth term, the sevent...

MATHS

The fourth term, the seventh term and the last term of a geometric progression are 10, 80 and 2560 respectively. Find its first term, common ratio and number of terms.

MEDIUM

Share

Study later

ANSWER

General term =ar

n−1

where, n=nth term

r=common ratio

a=first term

Now, ar

3

=10..............(1).

ar

6

=80............(2)

ar

n−1

=2560.................(3)

Dividing (2) by (1)

r

3

=8⇒r=2

in (1)

a×8=10⇒a=

8

10

in (3)

8

10

×2

n−1

=2560⇒2

n−1

=256⇒2

n−1

=2

8

⇒n−1=8⇒n=9

HOPE ITS HELP YOU........

MARK ME A BRAIN LIST..