TI-84 Calculator - 21 - Finding the derivative of a function by graphing

Picked one by one from a mixed channel. Transcript check: both title readers certain; 5 of 5 sampled certain picks confirmed by transcript, none failed. Channel rule: Include only course-style tutorial videos whose titles mark them as structured lessons (e.g. 'Lesson N', 'NN - Topic', 'Unit/Lesson', '... Tutor', '... Tutorial', 'Engineering Circuit Analysis', grade-level math, statistics/chemistry course parts) with plain descriptive titles; exclude the newer hook-titled pop-science explainers and any title using shouty caps or teaser phrasing.