
Spo�t�te plochu elipsy :
$$
  \frac{x^{2}}{a^{2}}+  \frac{y^{2}}{b^{2}}\leq  1,\quad a,b>0
$$
(u�ijte substituci   {$ x=ar\cos \varphi , y=br\sin \varphi  $}).