$\frac{m^4n^4}{mn^2}$

$9^2+30x+25$

$\lim_{x\to\infty}\left(x+\sin\left(x\right)\right)$

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

$\frac{d}{dx}\left(x^3+3x^2y^2+3y^3+y=o\right)$

$\left(49x^2-81\right)\left(-6x+x^2-91\right)$

$\left(1+\sin\left(x\right)\cos\left(x\right)\right)^2$