$\frac{1}{\cos\left(x\right)}-\sin\left(x\right).$

$\lim_{x\to0}\left(\frac{\tan\left(x\right)-\sin\left(x\right)}{x^3}\right)$

$x-3\left(x-1\right)<-2x+5$

$\cos2x+1=0$

$\int\left(6x+1\right)^4\left(2x\right)dx$

$\frac{-7x^3+x^5+35x}{-1+x^2}$

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