$\left(2x^3+3y^2\right)\left(4x^6-6x^3y^2+9y^4\right)$

$3x+2=6x-4$

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

$\frac{17}{0}$

$\lim_{x\to0}\left(\frac{\sqrt{x^4-x^4\sin^2\left(x\right)}}{1-\cos\left(x\right)}\right)$

$\lim_{x\to\infty}\left(\frac{4x+sin2x}{x}\right)$

$x^2+x-4$