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

$\left(-900\right)\cdot\left(-20\right)$

$27-\left(-4\right)$

$x^2-34x+289$

$\frac{dy}{dx}=k\left(4-x\right)\left(4-2x\right)^2$

$a^2-40a+400$

$9 ( 5 v - 3 ) + 412 u + 5$