A solid is defined by a surface:
x^2 + y^2 + z^2 ≤ b^2
Whereby, 0 ≤ x, 0 ≤ y, 0≤ z
The density varies in proportion to the distance from the centre.
Hence deduce the mass of the solid.
I assume i use sphereical polar coordinates, but not entirely sure where i go beyond that.
Any help is appreciated!