If you see a graph of a function, then you need to draw the derivative for this function. How can you draw it? I know you have to find some points, and find their slopes, and then put it on the graph and connect the points, but how can I estimate the slopes. I can only figure out the slope of 0 and positive slope or negative slope. Other than that, I can't tell the slope. Hope you can tell me. Thanks for help.