$x^2\frac{dy}{dx}-3xy+2x^2=0\:with\:y\left(1\right)=3$

$\lim_{x\to0}\left(\frac{1}{sen\left(x\right)\sqrt{x\cdot sen\left(x\right)}}-\frac{1}{x\sqrt{x\cdot sen\left(x\right)}}\right)$

$y=\left(-x+1\right)^2+5\left(x-1\right)+6$

$\int\frac{2x}{\sqrt{5-x^4}}dx$

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

$\left(3\right)^4\cdot\left(-3\right)^3$

$\left(x^2-\left(1+\frac{1}{x}\right)^2\right)$