Here’s the link I promised from today’s class: derivative as a function.
The red curve is the graph of the original function . The orange curve is the graph of the derivative of the original function .
You can drag the red point around on the graph of . The black dotted line is the tangent line to the graph at the red point. The corresponding orange point has the same -coordinate as the red point. The -coordinate of the orange point is the slope of the black tangent line at the red point. You can see, as you drag the red point around on the graph of the function , the orange point gets dragged around on the graph of the derivative .