Step 1:Derivative Of Sin X And Cos XThe 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 allimportant 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.
Creator: Krystal Marquez 
