Question

How to draw derivative function on the graph ?

Answer 1

The derivative function is just a function defined by the gradient of the original function. If you choose any x value and look at the gradient at that point on the original function, the gradient function at that same x value will have a y value that represents the gradient at that point on the original function.

example:

a turning point in the original function at point (x1, y1) will be represented in the derivative function as a root(where y = 0) because the gradient(ie. steepness) of the original function is zero at a turning point. so the gradient function would be through point (x1, 0) at this point