$\frac{\left(x+3\right)^2-\left(x-3\right)^2}{\left(x+2\right)\left(2-x\right)+x^2}$

$736\cdot12$

$sec\:xcos\left(-x\right)-sin^2\:x$

$\frac{s^2+1}{s^2+5}$

$-7\:.\:1\:+\:4$

$\frac{dy}{dx}\left(\left(x^2+y\right)^4=2y\right)$

$\lim_{x\to2}\left(\frac{9-t^2}{t+3}\right)$