## snickerzzz 2 years ago how do you find the sum of the series sigma n=0 ; 4 (cosn*pi) (3/4)^n

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1. RONNCC

use the equation maker

2. snickerzzz

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

3. RONNCC

are you sure it is till infinity?

4. snickerzzz

yes

5. TuringTest

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