$\left(+8\right)+\left(-13\right)-\left(-12\right)+\left(-17\right)-\left(-3\right)$

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

$\frac{dy}{dx}x\sin\left(y\right)=ay$

$a+a^2$

$csc\left(2x\right)+\frac{2}{\sqrt{3}}\:=0$

$\frac{x^3-2x^2+2x-2}{x^2+1}$

$\frac{1}{3x}+\frac{1}{7y}$