$\frac{\cos\left(v\right)}{\sin\left(v\right)}=\csc\left(v\right)-\sin\left(v\right)$

$\lim_{x\to0}\left(\frac{tan\left(6t\right)}{sin\left(2t\right)}\right)$

$-\sqrt{2}^2$

$3\cos\left(2x\right)-5\cos\left(x\right)$

$-x^2+9x+4.5^2$

$\left(m-n-y\right)^2$

$\frac{dy}{dx}-2y=e^{3\cdot x}$