$\frac{1}{y}y'\:=-\frac{e^x}{1+e^x}$

$\left(2x^2+\:3r^2\right)^4$

$\ln\left(x+4\right)-\ln\left(2\right)=4$

$\frac{dy}{dx}=\frac{4-2x}{3+2y}$

$\frac{1}{\cos\left(x\right)}-\frac{\cos\left(x\right)}{1+\sin\left(x\right)}=\frac{1}{\cos^2x}$

$\left(16a^2+5b^2\right)^2$

$\int\frac{z^3}{\sqrt{4+z^2}}dz$