this is a signals and systems question

Given the periodic signal shown in the figure, where A = 7 and 7 = 4, answer the following: a. What is the fundamental frequency of the waveform, x(t)? [1 Mark] b. Determine an expression for the Fourier series coefficients. [5 Marks] c. Determine and sketch the double-sided amplitude spectrum and double-sided phase spectrum (show at least 4 harmonic values). Clearly label and show axes and important values in both figures (frequencies, amplitudes, etc.) [6 Marks] d. What is the dc value of the signal? [1 Mark] e. What is the power contained in the first 3 harmonics? [2 Marks]