Question

What is the difference between ∆y/∆x and dy/dx

Answer 1

the first is the change in y, over the change in x, resulting in the slope (used for linear fcns)
the second is the derivative of y with respect to x, resulting in instantaneous slope eqn, yielding an eqn of fcn x, where plugging in any x-value yields a slope at that point

Answer 2

So it is only in linear funct'ns that dy/dx = ∆y/∆x?

Answer 3

yes, or constant zero variation fcns

Answer 4

Thanks

Answer 5

no problem