1. ## Power series expansion

This function :

$\displaystyle f\left( x \right) = \sin \left( {4x} \right)\cos \left( {2x} \right)$

have is the Power series expansion?
Give the radius and int of convergence

2. $\displaystyle \sin 4x\cos 2x=\frac{1}{2}\left(\sin 6x+\cos 2x\right)$

And then u may use de power series you know.