$\left(1-\tan\left(x\right)\right)^2+\left(1-\cot\left(x\right)\right)^2$

$\left(2x^{3}-4x^{7}\right)^{2}$

$\int_0^1x^2\cdot ln\:\left(x^3+3\right)dx$

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

$36x^2-18x-9$

$\lim_{x\to0}\left(\frac{log\left(1-x^2\right)}{log\:cos\:x}\right)$

$\frac{d}{dx}\ln\left(\frac{x-5}{x}\right)$