Question

If nth term of G.P is 2(0.5)^n-1,then the common ratio is

Answer 1

the common ratio is1:1

Answer 2

Solution:

Let a and r are first term and

common ratio of given G.p.

nth term = a×r^n-1---(1)

compare 2(0.5)^n-1 with (1),

we conclude that,

common ratio (r) = 0.5

Or

It is given that ,

an = 2×(0.5)^n-1

i) If n = 1

first term (a) = a1 = 2×(0.5)1-1

=> a1 = 2×1 = 2

ii) If n = 2

a2 = 2×(0.5)^2-1

= 2×0.5

= 1

iii ) Now ,

common ratio (r) = a2/a1

= 1/2

= 0.5

•••••