$f\left(x\right)=\left(\frac{\sec x-3x^2}{\cot+x+x}\right)^2$

$\left(x+2\right)\left(x-2\right)-\left(x-2\right)^2$

$\frac{dy}{dx}\left(4x^2+2y^2-3\right)$

$\left(a-6\:\right)\left(a\:+9\right)$

$\int\cos x\sen4xdx$

$\cos\left(a\right)\tan\left(a\right)\csc\left(a\right)\cot\left(a\right)$

$\frac{4}{3}x+\frac{2}{3}y-\frac{5}{6}z-\left(-\frac{2}{3}x+\frac{2}{9}y+\frac{8}{3}z\right)$