So F "moves" M a short distance parallel to itself. Whatare"the canonical isomorphisms of " and what is "the shape operator"?

ii)Derive the following formulas of the Gaussian and Mean Curvature

where and denote the principal vectors

Before I begin I managed to deduce from a previous problem that .

Now I would imagine that since that I would simply have wich would simply give which isn't the desired result.

So looking at both RHS and LHS I think I would get:

then from the RHS I get :

which has lead nowhere.

I'm not looking for the answer, but any hints would be greatly appreciated.