Originally Posted by
Archimedes Am I right in saying that
a) dy/dx = 1/7 Mr F says: Correct.
and
b) dy/dx = 1 / 8√x Mr F says: If you mean dy/dx = 1 /(8√x), then yes you're answer is correct.
so my rate of substitution would be (1/7) / (1 / (8√x))/ Is there a way to simplify this further? Mr F says: Yes. Note that (a/b) / (c/d) = (ad)/(bc) ...