$\lim_{t\to\frac{\pi}{2}}\left(\frac{\pi}{2}-t\right)\tan\left(t\right)$

$y^2+y^2$

$49m^2-64n^4^47m+8n^2$

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

$-\left(3x-2\right).\left(3x+2\right)$

$\left(y-x\right)dx+\left(y+x\right)=0$

$\int\frac{x+1}{\left(x^2+2x-1\right)^3}dx$