$\lim_{z\to0}\left(\frac{z^2}{1-cos\left(z\right)}\right)$

$27x+72$

$\frac{d}{dx}5\sqrt{6x^3}+x^2-9x+10$

$\left(2x-3y\right)^2+\left(2x+3y\right)^2-5x\left(2x-3y\right)+6y\left(2x-3y\right)$

$\ln\left(\frac{sen\:t}{cos\:t}\right)$

$\left[\left(-10\right):\left(5\right)\right]\left[\left(-16\right):\left(+2\right)\right]$

$cos^2x-sin^2x=1-2sin\left(x\right)$