$\frac{\left(2+tan^2x\right)}{\left(secx\right)}$

$\cos x=\frac{\sqrt{3}}{2}$

$x^2+25x+156.25$

$ydx-4\left(x+y\right)dy=0$

$\left(2xy^3-\sin\left(y\right)\right)dx+\left(3x^2y^2-x\cos\left(y\right)+\ln\left(y\right)\right)dy=0$

$3b-3-7b-7$

$2cos\left(\frac{x}{4}\right)=\sqrt{2}$