How do you find the derivative of f(x)=pitan(pir^2-5r)?

1 Answer
May 1, 2017

(2\pi^2x-5\pi)sec^2(\pi x^2-5x)

Explanation:

Assuming you meant f(x)=\pi tan(\pi x^2-5x)

\pi is a constant so we can ignore that. Since the inside of tangent is a function we have to use the chain rule. The derivative of tan(x) is sec^2(x) so we do get the following.
\frac{d}{dx}f(x)=\pi sec^2(\pi x^2-5x)(\frac{d}{dx}g(x))

Then we multiply the derivative of everything inside the parentheses which is
\frac{d}{dx}g(x)=2\pir-5

Combining them we get
\frac{d}{dx}f(x)=\pi sec^2(\pi x^2-5x)(2\pix-5)=(2\pi^2x-5\pi)sec^2(\pi x^2-5x)

You can expand it, but it might not look as clean.