Definition Fourier Analysis Let g(a) be an"arbitrary" periodic real function with period2丌 9()=∑ ikar gk e (k integer) 2丌 o eahae-ik'a da=2T Okk(orthogonality) 1 9k 2丌J0 g(a)eat da SMA-HPC⊙2003MT Partial Differential Equations 9