As a result of radioactive decay, heat is generated uniformly throughout the interior of the earth at a rate of around 30 watts per cubic kilometer. (a watt is a rate of heat production.) the heat then flows to the earth's surface where it is lost to space. let f(x, y,z) denote the rate of flow of heat measured in watts per square kilometer. by definition, the flux of f across a surface is the quantity of heat flowing through the surface per unit of time.
(a) suppose that the actual heat generation is 33w/km^3. what is the value of div f?