$13,9\:x\:6,5$

$\frac{dy}{dx}=3\sin\left(x\right)+5\cos\left(x\right)$

$x^2-3x-8$

$\:\frac{\left(8\sqrt{x^3+8}\right)}{3}+c$

$2csc^2x-1$

$\int_{-\pi}^{\pi}\left(x-x^2\right)\cos\left(nx\right)dx$

$y\left(x\right)\cdot y''\left(x\right)+\left(y'\left(x\right)\right)\cdot\cdot2=-\left(y\left(x\right)\right)\cdot\cdot2\cdot ln\left(y\left(x\right)\right)$