1. Prove that
2. Prove that
3. Prove that .
Thiis is basically the same method as two? Are the above correct?
the proof for 1 seems convincing except for placement of terms, but the one for 2 doesn't, as it stands.
To me, it would be more convincing if you substituted the expansion
r(x+h)=r(x)+hr'(x)+..., and likewise for s, into the second line, and then
threw out terms second order and above in h.