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Today's calculation of Integral 802

Source: 2012 Osaka Prefecture University entrance exam/veterinary

March 6, 2012
calculusintegrationgeometrygeometric transformationrotationratiologarithms

Problem Statement

Let kk and aa are positive constants. Denote by V1V_1 the volume of the solid generated by a rotation of the figure enclosed by the curve C:y=xx+k (x0)C: y=\frac{x}{x+k}\ (x\geq 0), the line x=ax=a and the xx-axis around the xx-axis, and denote by V2V_2 that of the solid by a rotation of the figure enclosed by the curve CC, the line y=aa+ky=\frac{a}{a+k} and the yy-axis around the yy-axis. Find the ratio V2V1.\frac{V_2}{V_1}.