Find the sum of first 20 terms of the geometric series 5/2+5/6+5/18+….. Question Find the sum of first 20 terms of the geometric series 5/2+5/6+5/18+….. in progress 0 Math Madelyn 3 weeks 2021-09-07T13:06:33+00:00 2021-09-07T13:06:33+00:00 2 Answers 0 views 0

## Answers ( )

r = t₂/t₁ a = 5/2 and n = 20

r = (5/6)/(5/2)

= (5/6) x (2/5)

r = 1/3 here r < 1

sn = a(1- rn)⁄(1 – r)

So, S₂₀ = (5/2) [1- (1/3)^₂₀]/[1-(1/3)]

= (5/2) [1- (1/3)^₂₀]/[2/3]

= (5/2) x (3/2) [1- (1/3)^₂₀]

= (15/4) [1 – (1/3)^₂₀]

GIVEN:–TOFIND:–•SOLUTION:–• We know that –

• Now put the values –