$\int\frac{\left(x^2\right)}{\left(\left(x^2\right)+1\right)^{\frac{3}{2}}}dx$

$\frac{dy}{dx}=\frac{x^2-1}{y^2+1}$

$\frac{sin\left(2x\right)}{cos\left(x\right)}$

$z=\frac{x}{y}$

$\frac{5a^2-19+8a}{3+a}$

$\int\frac{x^2-x-1}{\left(x^2+1\right)^2}dx$

$\frac{1}{3}+\frac{4}{6}$