$\frac{sinx-1}{\cos\left(x\right)}-\frac{\cos\left(x\right)}{\sin\left(x\right)-1}=\tan\left(x\right)$

$\frac{d}{dx}\left(\frac{1}{\left(x+1\right)\left(-x+1\right)}\right)$

$\int9dm$

$2z^2-38=0$

$-\left(5+4-9-6+2-7\right)$

$\lim_{x\to1}\left(\left(x^2-1\right)\left(\ln\left(x-1\right)\right)\right)$