$\frac{d^2}{dx^2}\left(50x^4+12x^3-15x^2+4x-10\right)$

$\:\frac{dy}{dx}\cos\left(x\right)=y\:\ln\left(y\right)$

$x^4+3x^3-3x^2-7x+6$

$f\left(x\right)=\frac{3x+13}{\left(x-4\right)\cdot\left(x+1\right)}dx$

$10\left(7+y\right)$

$\left(9m+n\right)\left(9m+n\right)$

$2\cos^2x\cdot\sec x+\cos x=0$