$\lim_{x\to0}\left(\frac{1}{\sin\left(8x\right)}\cos\left(7x\right)\right)$

$\frac{3x^3+2x^2-19x+7}{x+3}$

$\frac{sin^4x-cos^4x}{sin^2x}=2csc^2x$

$\csc2v-\cot2v$

$\left(m^3+n^3\right)^2+\left(m^3-n^3\right)^2=24$

$\frac{d}{dx}y=\frac{2x^2-3x+1}{2x+1}$

$\left(6n^2+8m\right)^3$