Question

how do you find the sum of the series sigma n=0 ; 4 (cosn*pi) (3/4)^n

Answer 1

use the equation maker

Answer 2

\[\sum_{n=0}^{\infty} 4 (\cos n \pi) (\frac{ 3 }{ 4 })^{n}\]

Answer 3

are you sure it is till infinity?

Answer 4

yes

Answer 5

Perhaps you can use some trig identities in conjunction with the ratio test.