Question

Find 11th term of G.P whose 5th term is 9 and common ratio is 2

Answer 1

Answer:

example:- We know that the formula for the nth term of an G.P is T

n

=ar

n−1

, where a is the first term, r is the common ratio.

It is given that the fifth term of G.P is T

5

=64 and the common ratio is r=2, therefore,

T

n

=ar

n−1

⇒T

5

=a×(2)

5−1

⇒64=a×(2)

4

⇒64=16a

⇒a=

16

64

=4

Now we have the first term a=4 and the common ratio r=2, thus,

T

12

=4×(2)

12−1

=4×(2)

11

=4×2048=8192

Hence, T

12

=8192.

Answer 2

Step-by-step explanation:

t5=9

ar^n-1 =9

ax2 ^4 =9

a=9/16

t11=9/2^4x 2^11-1

=9x 64

=276