$\frac{1}{\sec\left(x\right)}\cdot\frac{2}{\cot\left(x\right)}$

$\int_{3\pi}^{6\pi}\theta\:d\theta\:$

$\frac{dy}{dx}+y=100$

$e^{x+y}dx=-e^{2x-3y}dy$

$\lim_{x\to\infty}\left(\frac{1-\cos\left(x\right)\left(\sec\left(2x\right)\right)}{3x^3\csc\left(x\right)}\right)$

$\lim_{x\to0}\left(\frac{4^x-1}{8^x-1}\right)$

$-y^2-7y^2$