Sine Waves: Mapping the Unit Circle

Click on a star to rate it!

Join 0 others who rated this 0/5!

No votes so far! Be the first to rate this post.

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Beyond the Pulse: The Geometry of the Sine Wave

Defining Amplitude through the Geometry of Projection

While our first experiment established that the wave and circle are linked in The Pulse of a Circle , today we prove that the circle’s physical size is the “DNA” that determines the wave’s height.

Unit Circle to Sine Wave Projection
Mathematics of Waves: Unit circle animation mapping the rotation of a point to a sine wave.

Lab Results: The Radius-Amplitude Equivalence

If you look closely at the peak of each wave, you’ll notice it aligns perfectly with the furthest vertical reach of the circle. This isn’t a coincidence; it’s a geometric law.

In this experiment, we’ve moved from a standard unit circle \(R=1\) to a customized radius of 1.8. This change in the “Source” (the circle) dictates the “Pulse” (the wave).

The Key Takeaway:

  • The Input: The Radius of the circle.
  • The Output: The Amplitude of the sine wave.

By stretching the radius, we are essentially telling the wave how much “energy” or “height” it is allowed to have.

What’s Next? In our next blog, we’ll see what happens when we manipulate the Speed—turning this slow rotation into a high-frequency vibration.

The Mathematical Model: Scaling the Pulse

This relationship is a fundamental concept in Trigonometric Projections
and is a classic example of Simple Harmonic Motion.

The vertical displacement y is now scaled by the radius A.

y = A sin(θ)

By setting the radius to 1.8, the height y oscillates between 1.8 and -1.8, physically locking the wave’s peak to the circle’s edge.

The radius “DNA” is shown in Yellow.
The resulting wave traces a path in Electric Cyan.

Name: Source Code: Manim Implementation *

Leave a Comment

Scroll to Top