find the area enclosed by the curve x=3cost, y=2sint

Dear student,

x=3 cos t and y=2 sin t2x = 6 cos t   ....1 and  3y =6 sin t   ....2Squaring and adding 1 and 2, we get    4x2+9y2=36x29 + y24 = 1This is the equation of the ellipse.Now we find the area enclosed by the ellipseArea=403239-x2dx       =83039-x2dx       =83x29-x2+92sin-1x303       =83329-9+92sin-133-029+92sin-103       =83×9π4       =6π sq units

Regards

  • 12
Hint:
x=3cost
2x=6cost
​y=2sint
3y=6sint
Clearly,
(2x)2+(3y)2 = 36(sin2t+cos2t) = 36
so,
4x2+9y2=36, which is the equation of an ellipse.
Find area by integration for one quadrant and multiply it by 4.
 
  • 4
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