$\frac{1-\tan\left(x\right)}{\csc\left(x\right)-\sec\left(x\right)}$

$\left(x^4y\right)\frac{3x^4y^{-3}z}{6x^8y^2z^4}$

$3a-5b-8a-b-a-2b-5b-6a$

$-9\cos\left(x\right)+54\cos\left(x\right)^2-3$

$\int sin^4\left(\frac{x}{9}\right)cos\left(\frac{x}{9}\right)dx$

$\int x^2\left(8-e^3\right)dx$

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