Justifying Points of Inflection on the AP Calculus Exam

In this video we talk about justifying points of inflection, specifically on the AP Calculus Exam but everything is valid for any calculus class you might be taking. We go over how you’re likely to see the questions (either given a function of some sort or a graph of the first derivative) and how to justify in any circumstance. Sometimes we find the second derivative; sometimes we just base it on the graph of the first derivative. This is a really common thing to do on the free response questions (FRQs) and knowing what to do on the way into the exam will make you faster at doing it!

[@thespeedyyoshi]

Wait, for 2:57 why does it matter that f'(x) is increasing or decreasing? I thought it only mattered when f'(x) is positive or negative.

[@PrincessDaisyTseng]

quick question- once u have the positive and negative on the sign charts, when u go to justify when do u use increasing/decreasing VS positive/negative? I've always been a bit confused about that- thank you!!!!!

[@PrincessDaisyTseng]

not just for POI but when it asks max/min etc..

[@turksvids]

In addition to this video you might find these videos helpful for understanding those ideas:
justify max/min: ruclips.net/video/F5c8bgxOFJM/видео.html
using f' and f'' to graph f: ruclips.net/video/s4WCL907jrU/видео.html
Also there are a lot of FRQs with examples of write-ups for solutions. Here's my grid of video solutions: goo.gl/pT7JJ
Hope some of this helps!

[@slappyyummy]

thanks for the videos! are you going to make videos on the 2019 BC free response when they release?

[@turksvids]

Definitely! I usually post them within a day of the questions being released. Good luck!

[@slappyyummy]

Thank you!