Proving Identities: Cos^2(x)= (1+Cos2x)/2

[banfill_89]

Homework Statement

prove: cos^2(x)= (1+cos2x)/(2)

Homework Equations

i broke the cos^2(x) down to 1-sin^2(x)?

The Attempt at a Solution

 

[Defennder]

It's easier to start with the right hand side. Just apply the double angle formula on the right.

 

[banfill_89]

this is what i did:

= (1+cos2x)/(2)
= (1+ (2cos^2(x)-1))/(2)
= 2cos^2 (x)/2
cos^2(x)=cos^2(x)

look good?

 

[Defennder]

Yeah looks ok.

 

[banfill_89]

awsome thanksman