Answer:
a) 
b) 
c) 
Step-by-step explanation:
(a) Suppose that the actual heat generation is 27W/km3 What is the value of div F? div F- Include units)
For this case the value for div F correspond to the generation of heat.

(b) Assume the heat flows outward symmetrically. Verify that
where
. Find a α, (Include units.)
For this case we can satisfy this condition:
![div[\alpha (xi +yj +z k)]]=\alpha(1+1+1)=3\alpha](https://tex.z-dn.net/?f=div%5B%5Calpha%20%28xi%20%2Byj%20%2Bz%20k%29%5D%5D%3D%5Calpha%281%2B1%2B1%29%3D3%5Calpha)
And since we have the value for the
we can find the value of
like this:

(c) Let T (x,y,z) denote the temperature inside the earth. Heat flows according to the equation F= -k grad T where k is a constant. If T is in °C then k=27000 C/km. Assuming the earth is a sphere with radius 6400 km and surface temperature 20°C, what is the temperature at the center? 27,0 C/km.
For this case we have this:

And grad T represent the direction of the greatest decrease related to the temperature.
So we have this equation:

And we can solve for grad T like this:

Andif we integrate in order so remove the gradient on both sides we got:

For our case we have the following condition:


And we can solve for C like this:

So then our equation would be given by:

And for our case at the center we have that 
And we got:
