Maths-
General
Easy
Question
If the semi-vertical angle of a cone is
, then the rate of change of volume of the cone is
- Curved surface area times the rate of change of
- Base area times the rate of change of
- Base area times the rate of change of
- None of these
The correct answer is: Base area times the rate of change of 
Let
be the radius of the base,
the height and
slant height of the cone with semi-vertical angle
. Then,
and 
Let
be the volume. Then,


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