$+18\:-\:-27\:+\:-14\:-\:+23\:-\:-38\:-\:-15\:$

$4\cot x^2+4\cot x+1$

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

$un=\left|\left(-2\right)^n\right|n^30$

$\frac{dy}{dx}=e^{x-2y}$

$2x^2+8x-12=0$

$16\int\left(cos^2x\right)dx$