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

$\int\frac{1}{\left(1-x\right)^2\left(1+x\right)^2}dx$

$1x+1x+1x+1x$

$\lim_{x\to0}\left(\frac{x^3-1}{x^2}\right)$

$\frac{cos3x}{2sinxcosx}=\frac{1}{2}cscx-2sinx$

$\lim_{x\to0}\left(\frac{1-\cos\left(2\right)}{3x}\right)^{6x}$

$x^4+2x^2-y;\:x=2;\:y=0$