The Fourier series for an even function f(x) is given by
1
\(\frac{{{a_o}}}{2} + \mathop \sum \limits_{n = 1}^\infty {a_n}\cos nx + \mathop \sum \limits_{n = 1}^\infty {b_n}\sin nx\)
2
\(\frac{a_o}{2} + \mathop \sum \limits_{n = 1}^\infty {a_n}\cos nx\)
3
\(\mathop \sum \limits_{n = 1}^\infty {b_n}\sin nx\)
4
\(\frac{{{a_o}}}{2}\)