a trigonometry problem

[Jarif Mahbub Srabon]

If $m^2-n^2=16mn$ and $tanß+sinß=m$,then prove that $tanß-sinß=n$.

[sakibtanvir]

I am confused about the question .Why this $"\beta"$ angle is a variable when the equations tell,
$\displaystyle \sin \beta = \pm \sqrt {\frac{-1 \pm \sqrt {65}}{32}}$.But if the complex angles(!) are not allowed,then,
$\displaystyle \sin \beta = \pm \sqrt{\frac{-1+ \sqrt {65}}{32}}$.

[SANZEED]

I think the following assertion is correct to be proved:
If $m^2-n^2=4\sqrt {mn}$ and $m=\tan \beta+\sin \beta$,then show that $n=\tan \beta-\sin \beta$.