$\frac{cos\left(3x\right)}{sin^2\left(x\right)cos\left(x\right)}$

$93a^3x^2y-52a^2x^3y^2-129a^2x^2$

$-14+20x+8x^2$

$\lim_{x\to0}\left(\frac{1-x\cos\left(x\right)}{sin^23x}\right)$

$3x^{-7\sqrt{x}}$

$\left(-3\right)^2x\left(-3^5\right)$

$\lim_{x\to0}\left(\frac{2^x}{2.1^x}\right)$