We just started learning about trig identities. We're supposed to prove:

$\displaystyle \frac{(\sec\theta - \tan\theta)^2 + 1}{\csc\theta(\sec\theta-\tan\theta)}=2\tan\theta$

I reached the point where I was left with one long expression (too long too type) all over $\displaystyle \cos^2$. I really have no idea how to solve this.

Thanks in advance.