The function (f) with a period of 2π is defined by: f(x) = cosh (x - 2π) if x ∈ [π ; 3π] a) Determine the complex form of the fourier serie for this function(f) b) Determine the value of n=+∞ n=0 ∑...

The function (f) with a period of 2π is defined by:

f(x) = cosh (x - 2π)  if x∈[π ; 3π]

a) Determine the complex form of the fourier serie for this function(f)

b) Determine the value of

^n=+∞
_n=0∑1/(n²+1)

Note:cosh(x) = (e^x + e^-x)/2 and sinh(x) = (e^x - e^-x)/2