Finding the length of a curve in multivariable calculus. Sin/Cos identities problem..

Original problem:

Find the length of the curve. http://www.webassign.net/www29/symIm...851cf35972.gif

I have gotten this far:

$\displaystyle L = \int_{0}^{\pi/4} \sqrt{16sin^2(4t)+16cos^2(4t)+16tan^2(t)}dt$

but now I'm stuck because I don't perfectly recall the sin/cos/tan identities... I know that if I can get rid of the $\displaystyle sin^2$ and $\displaystyle cos^2$ I can change $\displaystyle tan^2+1$ to $\displaystyle sec^2$, which I can get the square root of and solve for... but what identities do I need to use? Thanks for any help.