The periodic function f(t) is defined on its period -212 by the formula: f(t)={ -t, when 210. t, when Ost2. a) Plot the function f(t) on the interval -818. b) Determine the period of the function. c) Determine, whether the function is odd or even? d) Find the mean value of the function on its period. e) Find the Fourier coefficients of the given function. f) Present the function by the Fourier series using the symbol . Present a mean value and next four terms of the Fourier series in the explicit form.