chain rule using trig functions So I have the following:
$$
y = cos(a^3 + x^3)
$$
This is what I got.
$$
y' = \cos(a^3 + x^3) \ ( -sin(a^3 + x^3) ) \ ( 3a^2 + 3x^2 )
$$
I'm not sure what to do after this? Would this be the final answer?

There is a wrong cosine function, a mistake (probably misspelling) in the argument of sine and a mistake in the third multiplier.
Is $y'$ equal to $\dfrac{\text d y}{\text d x}$? And $a$ is a constant or function?
