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Today's calculation of Integral 873

Source: 2013 Tokyo Institute of Technology entrance exam Problem 5

March 15, 2013
calculusintegrationconicsellipseanalytic geometrygeometrygraphing lines

Problem Statement

Let a, ba,\ b be positive real numbers. Consider the circle C1:(xa)2+y2=a2C_1: (x-a)^2+y^2=a^2 and the ellipse C2:x2+y2b2=1.C_2: x^2+\frac{y^2}{b^2}=1.
(1) Find the condition for which C1C_1 is inscribed in C2C_2.
(2) Suppose b=13b=\frac{1}{\sqrt{3}} and C1C_1 is inscribed in C2C_2. Find the coordinate (p, q)(p,\ q) of the point of tangency in the first quadrant for C1C_1 and C2C_2.
(3) Under the condition in (1), find the area of the part enclosed by C1, C2C_1,\ C_2 for xpx\geq p.
60 point