Derivative of sin x and cos x

Instructor: Gilbert Strang

http://ocw.mit.edu/highlights-of-calculus

The two key functions of oscillation have specially neat derivatives: The slope of sin x is cos x ! And the slope of cos x is – sin x.

These come from one crucial fact: (sin x) / x approaches 1 at x = 0. This checks that the slope of sin x is cos 0 = 1 at the all-important point x = 0.

Professor Strang connects sine and cosine to moving around a circle,

or up and down for a spring, or in and out for your lungs.

Subtitles are provided through the generous assistance of Jimmy Ren.

License: Creative Commons BY-NC-SA

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More courses at http://ocw.mit.edu

Subtitles are provided through the generous assistance of Jimmy Ren.