$\frac{\csc\left(x\right)-\sin\left(x\right)}{\cos\left(x\right)}=\cot\left(x\right)$

$\frac{\sec\left(\pi\right)+\tan\left(\pi\right)}{\cos\left(\pi\right)+\cot\left(\pi\right)}=\sec\left(\pi\right).\tan\left(\pi\right)$

$\lim_{x\to-\infty}\left(\frac{x^4-27}{x-9}\right)$

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

$\frac{dy}{dx}=-\frac{\left(-x^2+c\right)}{2}$

$2x^2-7x=-6$

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