If f(x) = 1 for 0 < x < π and -1 for -π < x < 0, then the Fourier coefficient a0 = ________.

For the function f(x) = x2 defined on -π ≤ x ≤ π, if its Fourier series expansion is f(x) = a02 + ∑n=1∞ (an cos(nx) + bn sin(nx)), then the values of the Fourier coefficients a0, an, and bn are:

In the Fourier series expansion of a periodic function f(x) over an interval of length 2K (period T = 2K), which term correctly represents the argument of the trigonometric functions?