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GATE 2025 AE – Question 42

Engineering Mathematics · Calculus: Limits, continuity, differentiability, chain rule, maxima and minima, integration · 2 marks · Numerical answer

The equation of a closed curve in two-dimensional polar coordinates is given by $r = \frac{2}{\sqrt{\pi}}(1 - \sin\theta)$. The area enclosed by the curve is ________ (answer in integer).

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Correct answer: 6

Explanation

The area is $\frac{1}{2}\int_0^{2\pi}r^2d\theta = \frac{1}{2}\cdot\frac{4}{\pi}\int_0^{2\pi}(1 - 2\sin\theta + \sin^2\theta)d\theta = \frac{2}{\pi}(2\pi - 0 + \pi) = 6$.