Consider the following periodic sawtooth waveform, x(t): x(0) 0 0 n27 72.71 a) First show that the trigonometric Fourier series (FS) expansion for the following periodic waveform, x(t), is given by: 20 = 0.25, a. [1 - cos(nn)], bn = (1) [Note: Here are some useful integration formulas: 1 1 1 x cos(ax)dx = cosax + = xsinax ſx sin(ax)dx=--cosax + 1 ar? b) From the trigonometric FS expansion given by (1), find the compact trigonometric FS representation of x(t) (in terms of cosines) and sketch its amplitude and phase spectra. an av (zemdr = (a a a