- #1

newbe318

- 12

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I was looking at the solution for problem 6 and I am confused on taking the derivatives of the function f(x)= cos^2 (x)

I took the first derivative and did get the answer f^(1) (x)= 2(cos(x)) (-sin (x)), but how does that simplify to -sin (2x)?

Is there some trig identity that I am not aware of?

Your help would be much appreciated, since I have a final Friday.

Thank you.