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

$\left(x^2+y^2\right)dx-5xydy=0$

$-4\:x\:-3$

$ax^2+10x+25$

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

$\left[\frac{\left(t^3-2t+1\right)}{\left(t^4+3\right)}\right]^{13}$

$\int\left(\frac{4x+9}{4x^2+18x^4}\right)dx$