Plot derivative of a function

[cyrille de brébisson]

Hello,

Quote:Cool thanks that worked! Wonder why the =X is required?

F2(X) needs to be a function that, when evaluated with a given X variable returns a Y.

if F1(X)=SIN(X)
and F2(X)=dF1(X)/dX
note that the X in the F2(X) definition is NOT the same as the X in F2(X)...
What it is (in programing terms), is a local variable, which has the same name, but is different.
dF1(X)/dX is NOT a function that varies with X as you can calculate it regardless of the value of X...
dF1(X)/dX is the same as dF1(A)/dA for example.

If you restate your problem as: F2 is the result of the EVALUATION of the derivative of F1 with respect to a variable at a given value of a variable, then you see that you do indeed have 2 variables to contend with, not one.

the syntaxe: dF1(X)/dX=value is a shorthand for dF1(X)/dX | X=X (|=WHERE)

Cyrille