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← JEE Main 2022 · 27 Jun · Shift 2
MathematicsInteger+4 / -1Question 27 of 90

JEE Main 2022 · 27 Jun · Shift 2, Mathematics question 27

If the area of the region {(x,y):x2/3+y2/3≤1, x+y≥0, y≥0}\left\{(x,y):x^{2/3}+y^{2/3}\le1,\ x+y\ge0,\ y\ge0\right\} is A, then 256Aπ\dfrac{256A}\pi is equal to ______.

Answer and worked solution

Official answer: 36

Astroid area. x2/3+y2/3≤1x^{2/3}+y^{2/3}\le1 has area 3π8\frac{3\pi}8; the upper half is 3π16\frac{3\pi}{16}.

Cut by x+y≥0x+y\ge0. In the second quadrant the line y=−xy=-x meets the curve at (−122,122)\left(-\frac1{2\sqrt2},\frac1{2\sqrt2}\right); removing the part below the line leaves A=9π64A=\frac{9\pi}{64}.

Value. 256Aπ=36\dfrac{256A}\pi=36 (confirmed numerically).

Answer: 36