Practice corner: derivatives
Below you have two graphs - if you click on the forward button, at each click you will see the following appear in sequence: 
1) on the right hand panel you have a function  (appearing in blue), with its equation; then a point  on the function; then the tangent line to the function  at point , and finally the slope of the tangent line to  at point , which is coloured in green. 
2) On the left hand panel you have instead a point  , then a box where you can input the expression for the derivative of .