$\frac{1}{cos\left(\theta\right)}-sin\left(\theta\right)tan\left(\theta\right)$

$\left(6x^4-5xy^3\right)^3$

$\lim_{x\to-\infty}\left(\sqrt{x^2+1}-\sqrt{x^2-1}\right)$

$\left(12n-9\right)\left(x+3y\right)$

$\frac{d}{dx}ln\left(\frac{\left(e^x\right)}{1+e^x}\right)$

$16y^2+14.0013468013467=-25.8730274688522$

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