$\sin^2\left(x\right)+cos^2\left(\frac{-13}{30}\right)=1$

$\int\frac{e^x}{\left(9-e^x\right)^2}dx$

$\int x\left(8x-4\right)^2dx$

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

$\frac{x^2-4x+4}{3x^2-5x+3}$

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

$\lim_{x\to\infty}\left(\cos\left(x\right)+\tan\left(x\right)\right)^x$