Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Lissajous figures circle problem

  1. Feb 4, 2009 #1
    1. The problem statement, all variables and given/known data

    Show that the two inputs given by x = Asin(wt) and y = Acos(wt) would display a circle of radius A on the display of an oscilloscope?

    2*pi*f = w

    This is a bonus lab question i am supposed to look online and research how to do but cant find anything that explains it well. Can anyone please help? Thanks!!!
     
  2. jcsd
  3. Feb 4, 2009 #2

    Delphi51

    User Avatar
    Homework Helper

    Re: cirlce

    Circles are pretty complicated. Have you ever seen that demo where a wheel is rolled along the ledge below the chalkboard and a piece of chalk on the turning wheel makes a graph on the board? That graph of its height is a sine wave.

    In math theory, you always talk about the unit circle. The x coordinate on the unit circle is cos(A) and the y coord is sin(A), right? Imagine the point moving around the circle so its angle is A = wt. That should give you pretty much the same equations you were given for the scope.
     
  4. Feb 5, 2009 #3
    Re: cirlce

    The problem described is an example of Lissajous figures.Try googling.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook