I need help for the Fourier series development.

Justify the convergence of the general term numerical series; Where n is a natural integer Using the Fourier series development of "for : = 0 and r = s, calculate: & Step 1: consider nth term: (-1)" Hi + 1 Step 2: See the value of the nith term when n-es. lim (-1) (-1) 0 +1 (-1) The value of (-1]" will be either 1 or -1. In either case, lim=0 So, the series is convergent and converges to 0.Step 3: Find the value of limit for second nth term when n-0 lim DO So, the series is convergent and converges to 0