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The area (in sq. units) of the region enclosed by the curve 9x2+4y2=369x^2 + 4y^2 = 36 is

Solution

✅ Correct Option: 3

The equation 9x2+4y2=369x^2 + 4y^2 = 36 has both x2x^2 and y2y^2 terms with different coefficients that are added together. This is an ellipse.


The standard form of an ellipse is x2a2+y2b2=1\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1.

Dividing the entire equation by 36:

9x236+4y236=3636\frac{9x^2}{36} + \frac{4y^2}{36} = \frac{36}{36}

x24+y29=1\frac{x^2}{4} + \frac{y^2}{9} = 1


From x24+y29=1\frac{x^2}{4} + \frac{y^2}{9} = 1:

a2=4a^2 = 4, so a=2a = 2

b2=9b^2 = 9, so b=3b = 3


The area of an ellipse is given by A=πabA = \pi ab.

A=π×2×3A = \pi \times 2 \times 3

A=6πA = 6\pi

Therefore, the area of the region enclosed by the curve is 6π6\pi square units.

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