Differential Equation with a Discontinuous Forcing Function

Consider the equation , where is a square-wave step function and is the oscillation of a spring-mass system in resonance with the square-wave forcing function. The graph of is drawn in purple and that of in blue. Using Laplace transforms, this solution is more compact than using a Fourier series expansion of the forcing function.
The first three terms of the Laplace transform of the homogeneous solution for are: . The Laplace transform of the forcing function is . The phase synchronization between input and output gives rise to resonance.
  • Contributed by: Stephen Wilkerson
  • (United States Military Academy West Point, Department of Mathematics)



  • [Snapshot]
  • [Snapshot]
  • [Snapshot]


This example comes from [1], Section 5.6, Differential Equations with Discontinuous Forcing Functions.
[1] J. R. Brannan and W. E. Boyce, Differential Equations with Boundary Value Problems: An Introduction to Modern Methods and Applications, New York: John Wiley and Sons, 2010.
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.