2. P. 541. In Active Figures 18.20a and 18.20b,notice that the amplitude ofthe component wave for frequency f rs large, that for3 f is smaller, and that for 5 f smaller still. How do we know exactly how much amplitude to assign to each frequency component to build a square wave? This problem helps us nd the answer to that question- Let the square wave in Active Figure 18.20: have an amplitude A and let 2' =0 be at the extreme left ofthe gure. So, one period Tof the square wave is described by +' (r) [A o