$\frac{x^7}{x^{15}}$

$\frac{\sin\left(n\right)}{\cos\left(n\right)}+\frac{\cos\left(n\right)}{1+\sin\left(n\right)}=\tan\left(x\right)$

$\sin\left(x\right)^2=-6\cdot\sin\left(2x\right)$

$-10v+6v$

$\lim_{x\to-1}\left(\frac{\sqrt{x+3}-2}{\left(x+1\right)\left(x-1\right)}\right)$

$n^2+16n$

$4^x-2^x-12=0$