$\left(x+y\right)^2-2\left(x+y\right)\left(x-y\right)+\left(x-y\right)^2$

$\frac{2a^4-3a^2+a-1}{a^3}$

$\lim_{x\to6}\left(\frac{2x^2-12x}{x^2+8x+12}\right)$

$\left(t^{\sqrt{17t}}\right)$

$\frac{d^2u}{dxdy}+u=0$

$\left(5x^4-\frac{25}{16}x^2\right)$

$\int sen^2ocos^3odo$