Find the equation of the ellipse whose centre is (- 2, 3) and whose semi - axis are 3 and 2 when the major axis is (i) parallel to x - axis (ii) parallel to the y - axis.

Given that we need to find the equation of the ellipse whose centre is (- 2,3) and whose semi - axis are 3 and 2.


(i) If major axis is parallel to the x - axis.


We know that the equation of the ellipse with centre (p,q) is given by .



Since major axis is parallel to x - axis a2>b2.


So, a = 3 and b = 2.


a2 = 9


b2 = 4


The equation of the ellipse is




4(x2 + 4x + 4) + 9(y2 - 6y + 9) = 36


4x2 + 16x + 16 + 9y2 - 54y + 81 = 36


4x2 + 9y2 + 16x - 54y + 61 = 0


The equation of the ellipse is 4x2 + 9y2 + 16x - 54y + 61 = 0.


(ii) If major axis is parallel to the y - axis.


We know that the equation of the ellipse with centre (p,q) is given by .



Since major axis is parallel to y - axis b2>a2.


So, a = 2 and b = 3.


a2 = 4


b2 = 9


The equation of the ellipse is




9(x2 + 4x + 4) + 4(y2 - 6y + 9) = 36


9x2 + 36x + 36 + 4y2 - 24y + 36 = 36


9x2 + 4y2 + 36x - 24y + 36 = 0


The equation of the ellipse is 9x2 + 4y2 + 36x - 24y + 36 = 0.


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