edit ... just figured out the second one..

the first one I still can't get my head around!

i'll run through what i'm doing ..

so,

d/dx[2y]^1/2

= 1/2*[2y]^-1/2

= 1/2*(1/sqrt(2y)

=1/(2*sqrt(2y)) ....

i should be getting 1/sqrt(2y) ... where am i going wrong?