These are scribbles written for the sake of increasing learning retention. To me, writing down my own thought after experiencing something with 5 senses is a good exercise for mental strength. Don't believe me, please.
Reintroduction to Calculus 21 April 2017
If we were to measure the derivative of f(x) which is the slope at certain point where tangent line touch the graph, we have to draw another line that seems to touch the point very close to it. Read on.