JEE Main202229 Jun 2022Evening ShiftMathematicsArea Under CurvesActual
For real numbers a , b a > b > 0 , let Area x , y : x 2 + y 2 ≤ a 2 and x 2 a 2 + y 2 b 2 ≥ 1 = 30 π and Area x , y : x 2 + y 2 ≥ b 2 and x 2 a 2 + y 2 b 2 ≤ 1 = 18 π Then the value of a - b 2 is equal to _____.
Correct answer
0
Step-by-step solution
We know that area of circle = πr 2 ( r is radius of circle) and area of ellipse = πab (where a   &   b are length of semi major and semi minor axis) Now given area between circle and ellipse ⇒ π a 2 - π a b = 30 π .....(i) And ⇒ π a b - π b 2 = 18 π ....(ii) On subtracting equation (i) - (ii), we get a - b 2 = a 2 - 2 a b + b 2 = 12 .