SOLUTION: prove (we have to work with the left side) cos(2u)=cos^2u

Question 155226This question is from textbook precalculus
: prove (we have to work with the left side)
cos(2u)=cos^2u This question is from textbook precalculus

Found 2 solutions by stanbon, jojo14344:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Are you sure you are being asked to prove this
is an identity. It is not an identity.
Possible you are being asked to solve this
equation. That can be done.
------------------
Cheers,
Stan H.
Answer by jojo14344(1513) (Show Source): You can put this solution on YOUR website!

By double -Angle Formula:

So,

By Pythagorean Identities:

Therefore,
----------->
Thank you,
Jojo
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