$\frac{cot^2x}{cot\:x-1}+\frac{tan\:x}{1-cot\:x}$

$-18\:x\:-45$

$\left(2y^3+7\right)^2$

$x^3-2x^2=0$

$\lim_{n\to\infty}\:\frac{\left(2^{n+2}+1\right)}{2^n+1}$

$\int_0^{\frac{1}{2}}\left(\sqrt{3x+1}\right)dx$

$1-2sin^2\left(\theta\:\right)=\frac{1-tan^2\left(\theta\:\right)}{1+tan^2\left(\theta\:\right)}$