Math Primer: Trigonometry 101 - Flash 3D: Animation, Interactivity, and Games - page 146

off to the nearest integer, and this number is divided by 10000 to get a number with a
decimal point. The net effect of multiplying and then dividing by 10000 is to round the
sin and cos functions off to the nearest four decimal points.

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// display the numerical values
degrees_txt.text = angleInDegrees;
sin_txt.text = Math.round(10000*Math.sin(angleInRadians))
/10000;
cos_txt.text = Math.round(10000*Math.cos(angleInRadians))
/10000;
};

Exercise 5.4: Using Sine Wave Motion

Now that we have seen what a sine wave looks like, let's take a look at an example of
sinusoidal motion. One of the first and most classical demonstrations of this appeared
in the study of the motion of a clock's pendulum, a major advance in technology at the
time. Open 5_4_clockWatcher.swf in the Chapter 5 Completed_Exercises folder to
see the motion of a pendulum and test your powers of observation like a true scientist.
For our pendulum we will assume that all of its weight is concentrated at a point in the
bottom, and we'll live in an ideal world that has no friction.

Figure 5.26 Sinusoidal motion in a pendulum