Write as a decimal.

Question

0

661

2

+1310

Write $\frac 15+\left(\frac 15\right)^2+\left(\frac 15\right)^3+\left(\frac 15\right)^4$ as a decimal.

AWESOMEEE May 25, 2015

+128596

+10

Best Answer

We can write this infinite sum, thusly......

S = a₁ / [1 - d] where a₁ is the first term and "d" is the common difference ...(1/5) in this case...so we have

(1/5) / [ 1 - 1/5) = (1/5) / (4/5) = (1/4) = .25

CPhill May 25, 2015

CPhill · Answer 1 · 2015-05-25T02:50:05

We can write this infinite sum, thusly......

S = a₁ / [1 - d] where a₁ is the first term and "d" is the common difference ...(1/5) in this case...so we have

(1/5) / [ 1 - 1/5) = (1/5) / (4/5) = (1/4) = .25

AWESOMEEE · Answer 2 · 2015-05-25T12:41:58

BTW, i look at the explanations