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Is there an equation for sinusoid about a curve?

  1. Jul 6, 2011 #1
    The typical sine wave y = sin(x) has its center line as y = 0. Is there any equation I can represent a sine wave that has a center line as a curve? Something like the edge of the cookie cutter:
    http://www.pmeartsandcrafts.com/4010-16826-large/round--wavy-edge-cutters-xxxl.jpg [Broken]
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jul 6, 2011 #2
    You basically need a sine wave along a curved dimension. Here is one function that achieves this.

    r = a - b*cos(w*t)
    a is the radius of center circle.
    b is the amplitude of sine wave.
    w is the frequency of the wave. I chose integer value for w to make sure the sine wave ends where it started.
    t is the angle, goes from 0 to 2pi.

    Here is an http://shareimage.org/images/uh7fobqbcznu724zhu.png" with a = 5, b = 0.5, w = 10.
    Last edited by a moderator: Apr 26, 2017
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