Question

Find dy/dx of (1+cos^2 7x)^3

Answer 1

chain rule for this one

Answer 2

\[\frac{d}{dx}(1+\cos^2(7x))^3=3(1+\cos^2(7x))^2\times (2\cos(7x))\times (-\sin(7x))\times 7\]clean up with algebra

Answer 3

So, How do you find d/dx of cos^2(x)? I can't quite remember if it is just 2cos(x), or if you have to do something special to it.

Answer 4

chain rule
first take care of the square, then take care of the cosine

Answer 5

the derivative of \(f^2(x)\) is \(2f(x)f'(x)\)

Answer 6

So, it will become 2cos(x), then become -2sin(x)?

Answer 7

no
the derivative of some function squared is two time that function, times the derivative of that function
more succinctly written as \[(f^2)'=2ff'\]

Answer 8

So you use the product rule?