$\left|-8+7-\left(13\right)-5\right|$

$\left(csc^2x-1\right)sec^2x$

$-1^2-2\cdot\left(-1+2\right)$

$\int\left(x^3-2x^5\right)cos\left(\frac{x}{4}\right)dx$

$\frac{dy}{dx}8ln\left(\frac{15}{x}\right)$

$\left(\left(-\frac{2}{3}\right)\right)xy+\left(\frac{1}{7}x^3\right)\cdot\left(\left(-\frac{2}{3}\right)\right)xy+\left(\frac{1}{7}x^3\right)$

$\frac{d^2}{dx^2}\left(9\sin\left(x\right)\cdot\cos\left(x\right)\right)$