$\frac{\left(-cos^2x-2sin\left(x\right)\right)}{cos^2\left(x\right)}$

$\int\left(\frac{3e\cdot\sin\left(4x\right)}{\sec\left(4x\right)}\right)dx$

$-9.7\:+\:-5.4$

$\int\sin^6\left(3x\right)\cos^3\left(3x\right)dx$

$k-9-5k$

$3x+9y-2z=19$

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