# Math Help - Derivative

1. ## Derivative

Can anyone help me with the derivative of 5xArctan(2x)???

Thank you!!

2. Originally Posted by BKennedy
Can anyone help me with the derivative of 5xArctan(2x)???

Thank you!!

Use the product rule

let

$f(x)=x$ and $g(x)=\tan^{-1}2x$ then
$f'(x)=1$ and $g'(x)=\frac{2}{1+4x^2}$

by the product rule we get...

$\frac{d}{dx}(fg(x))=f'(x)g(x)+f(x)g'(x)=1 \cdot \tan^{-1}(2x)+x \cdot \frac{2}{1+4x^2}$

Just simplify from there