$\frac{1-\tan\left(36\right)}{1+\tan\left(36\right)}=\tan\left(9\right)$

$4x^5+2x^2+nx$

$42-18:\left(-6\right)$

$3087-2622.07143$

$20+90+51^2^2$

$x^2-13x-14$

$\frac{\frac{1}{\cos\:\left(a\right)}+\frac{1}{\sin\:\left(a\right)}}{1+\frac{\sin\:\left(a\right)}{\cos\:\left(a\right)}}=\frac{1}{sen\:a}$