$lnx\:-ln\left(x+2\right)\:+\:ln\left(4-x^2\right)$

$\cos\left(x\right)-2\sin\left(x\right)\cos\left(x\right)+\cos\left(x\right)\sin\left(x\right)^4$

$121x^{10}-100$

$x^2+20x^2-6x$

$\left(-4x-20\right)^2$

$\left(x^2+6x\right)-\:\left(x-3\right)\:$

$\int_0^5\sqrt{25-x^2}dx$