$\cos255^{\prime}=\frac{\sqrt{2}-\sqrt{6}}{4}$

$8x^4-2x^2=0$

$2x+y;\:x=7;\:y=10a$

$4\log\left(2\right)-\frac{1}{3}\log\left(64\right)+2\log\left(6\right)+\log\left(x\right)$

$\frac{\frac{d}{dx}\left(2e^x\right)}{\left(x\right)}$

$\frac{\sin^2m}{\cos^2m}+\cos m$

$f\left(x\right)=\frac{x^{5}\left(x-5\right)^{6}}{\left(x^{2}+5\right)^{8}}$