What is the Cosine Double Angle Identity for Cos²(wt+a)?

[Peon666]

Cos^2 (wt+a) = 1+Cos(2wt+2a)

?

 

[tiny-tim]

Hi Peon666!

(have an omega: ω and try using the X² tag just above the Reply box )

Cos^2 (wt+a) = 1+Cos(2wt+2a)

?

(hmm … there's a factor of 2 missing …)

You need to learn all the standard trigonometric identities …

this one is 2cos²x = 1 + cos2x

(rather like 2sin²x = 1 - cos2x …

try adding and subtracting them )

 

[Peon666]

I'm indeed ashamed that I'm studying Signals course and not aware of complete trigonometric identities. Thanks a lot for your help.