$\frac{dy}{dx}=0.09\cdot t^2-0.6\cdot k\cdot t+k^2$

$\sqrt{5a^5b^{-7}c}$

$\lim_{x\to0}\left(\frac{\cos4x-3t}{\sen^{2}3x}\right)$

$\frac{-5x^2-x^4+x^2-2}{x^2+1}$

$2x^2-25x-33$

$\lim_{x\to0}\left(1-\cos\left(x\right)\cot\left(x\right)\right)$

$-x^2-y^2+2x^2-3y^2-x^2-3y^2$