Sketch the appropriate curves. A calculator may be used.

In checking electric circuit elements, a square wave such as that shown in Fig. 10.45 may be displayed on an oscilloscope. Display the graph of  

on a calculator, and compare it with Fig. 10.45. This equation gives the first three terms of a Fourier series. As more terms of the series are added, the approximation to a square wave is better.

y = 1 + - sin + TX 4 4 sin 3 4