$\left(-3cd\right)\cdot\left(8dk^2\right)\cdot\left(-3c^3k^4\right)$

$\left(-2+3b\right)^2$

$\int\frac{x^2+1}{\left(x^2+2\right)\left(x-2\right)}dx$

$\frac{\cos^2x+\tan^2x}{sin^2\:x}$

$\int\frac{x+1}{\left(x^3-2x^2+4x\right)}dx$

$\frac{d}{dx}\:cosy=3x^3-3$

$\int_3^6\left(\frac{1}{\sqrt{36-x^2}}\right)dx$