$\frac{cot\left(x\right)+tan\left(x\right)}{-sec\left(x\right)}$

$\int2\left(x-4\right)^2dx$

$\left(3a+5\right)\left(3a-8\right)$

$\int\frac{x^3}{\sqrt{9x^4+6x^2-1}}dx$

$\lim_{x\to-7}\left(\frac{x^2+6x+21}{x+7}\right)$

$\lim_{x\to\infty}\left(\frac{\sqrt{4x^4+x^2+1}}{x^2+1}\right)$

$\lim\:_{x\to\:-\frac{\pi\:}{2}}\left(\frac{1-sin\:x}{1+cos\:2x}\right)$