Question

The volume of solid of revolution when rotated along x-axis is given as _____________

(a) \(\int_a^b πy^2 dx \)

(b) \(\int_a^b πy^2 dy \)

(c) \(\int_a^b πx^2 dx \)

(d) \(\int_a^b πx^2 dy \)

This question was addressed to me in exam.

Origin of the question is Volume of Solid of Revolution in division Integral Calculus of Engineering Mathematics

Answer 1

Correct choice is (a) \(\int_a^b πy^2 dx \)

To explain: Volume is generated when a 2d surface is revolved along its axis. When revolved along x-axis, the volume is given as \(\int_a^b πy^2 dx \).