$\frac{dy}{dx}=x\sqrt{-x-1}$

$\lim_{x\to2}2x^3-3x^2+4x-9$

$\int\tan^3\left(x\right)\cdot\sqrt{\left(tan^2\left(x\right)+1\right)}dx$

$\left(z^{x}\right)\left(xz\sos\right)$

$\frac{\tan\left(x\right)-1}{\tan\left(x\right)+1}=\frac{\sin\left(x\right)-\cos\left(x\right)}{\sin\left(x\right)+\cos\left(x\right)}$

$\left(mn-xy\right)\left(mn-xy\right)$

$\frac{dy}{dx}=\:\:\frac{xy}{\left(x^3+x\right)}$