Calc 1: Differential Calculus

Lecture 15: The Derivative of the Trigonometric Functions

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Video 1: Trigonometric Derivatives

In this video, we discover the differentiation formulas for sine, cosine, tangent, secant, cosecant, and cotangent.

If you haven't gotten around to watching the 3Blue1Brown video introducing the derivative rules through geometry, I highly recommend you take a look now. He gives a very nice geometric explanation for why the derivative of sin(x) is cos(x). I give the same argument in a later video (Lecture 20), when we introduce differentials. But I just use a static picture, and the 3Blue1Brown video uses animations.

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Video 2: Trigonometric Limits

Here is a video about computing so-called "trigonometric limits", which are limits having indeterminate forms (like 0/0) that involve trigonometric functions.