Calculus

Let this be a three-dimensional scalar field

 f(x,y,z)=(1)/(x^2+y^2+z^2)-z

 

Determine the gradient grad f and the value of |grad f| in spherical coordinates.

Note

The negative "z" is not part of the fraction 1/(x^2+y^2+z^2). It is indeed separate.

So the question would read: fraction -z
Where the fraction is 1/(x^2+y^2+z^2).