Estimating Instantaneous rate of change (IROC) using secants

The slope of the secant line gives us the average rate of change (AROC).

This is a video where instantaneous rate of change is being considered for a quadratic function. The point of the video is that as x gets very, very close to 5, the difference between x and 5 gets very, very close to zero, and thus we get very, very close to the value of the tangent slope.

Technical details: Initially post-produced in Permiere Pro, exporting was a problem, so I re-did the whole post-production in OpenShot, which never seems to pose a problem to this day. Music is from the extensive YouTube stock music collection. I chose a jazzy tune by Topher Mohr and Alex Elena, called "Rubber Necking". The tempo was slowed down slightly to fit the video's length.