Calculate: $\lim \limits_{(x,y) \to (2,1)} \frac{\tan(y-1)\sin^2(x-2y)}{(x-2)^2+(y-1)^2}$

Question

$\lim \limits_{(x,y) \to (2,1)} \frac{\tan(y-1)\sin^2(x-2y)}{(x-2)^2+(y-1)^2}$

I tried this change of variables: $s=x-2, t=y-1$, therefore:

$\lim \limits_{(s,t) \to (0,0)} \frac{\tan(t)\sin^2(s-2t)}{s^2+t^2}$

And I'm pretty much stuck here.

Thanks