We posted at about the same time.

Thank you, the Physics package is what I needed

We posted at about the same time.

Thank you, the Physics package is what I needed

My apologies. Obviously my 'answer' is wrong.

I still want to know what to enter for ∂F/∂y'

The answer should be y'(x)/sqrt(1+(y'(x))^2)

(That is the right answer)

My apologies. Obviously my 'answer' is wrong.

I still want to know what to enter for ∂F/∂y'

The answer should be y'(x)/sqrt(1+(y'(x))^2)

(That is the right answer)