Ok I've come across a similar question which I am having troubles with, this time its the method
A vector field exists so that:
where
C is the path on the sphere which is
Prove that
Now im not entirely sure how to best approach this, i can easily see:
Though i am unsure how to encorporate the path to deduce zero.
I guess the main thing throwing me here is there f(r) i have r, and i could use sphereical coordinates, but I do not know f(r), just part of it (the r). Do i assume f(r) = r?? Then convert into sphereical coordinates, work out normal etc ?