Im unable to simplify this, ive tried but i just cant seem to get it to work.. it goes a little like this -

I understand that $\displaystyle tan(arcsinx) = \frac{x}{\sqrt{1-x^2}} $

But i need to simplify this -

$\displaystyle \frac{1}{256} [\frac{tan^3(arcsin\frac{x}{4)}}{3} + tan(arcsin\frac{x}{4}) $

Which i think should eventually end up like this -

$\displaystyle \frac{x(x-4)(x+4)(x^2-24)}{384[16-x^2]^\frac{5}{2}} $

Can someone show me the steps please? Btw, i posted this in calculus, because it had origianlly started off as an integration question.