The Fourier series of the function,<br>\[\begin{array}{*{20}{c}} {{\text{f}}\left( {\text{x}} \right) = 0,}&amp;{ - \pi The convergence of the above Fourier series at x = 0 gives

Correct Answer: $$\sum\limits_{{\text{n}} = 1}^\infty {\frac{1}{{{{\left( {{\text{2n}} - 1} \right)}^2}}} = \frac{{{\pi ^2}}}{8}} $$