$\sec\left(x\right)=2.3495$

$2cos^2x-1=1-2cos^2x$

$\lim_{x\to\frac{\pi}{2}}\left(x+\frac{\pi}{2}\right)secx$

$\frac{dy}{dx}=\frac{2x^2+y^2}{xy}\:$

$\lim_{x\to0}\left(\frac{5-5cos\left(x\right)}{e^x-x-1}\right)$

$4x^2y^7+2x^5y^3-10x^4y^9$

$\left(8bd^9+13a^{10}b^2\right)^2$