Question

how do you find the geometric sum of (2/5)^(2k)

Answer 1

let k = 1... 1st term = (2/5)^2 2nd term = (2/5)^4 3rd term (2/5)^6

r = 4/25

since |r| < 1 then you can find the limiting sum using

\[\S = a/(1 - r)\]

S = (4/25)/(1 - 4/25)

S = 4/25 x 25/21

The limiting sum is 4/21

Answer 2

thank you! i get it