Thread: dy/dx

i am kind of confused on which rule to use?

Find dy/dx

y=cos^2 (3x)+sin^2(3x)


step by step

Hello, Emmeyh!

This is a trick question . . .

Differentiate: .

We know that: . . . . right?

So the function is actually: .

Therefore: .

And you should get the same answer doing it "the long way."
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