Chapt.12: Orthogonal Functions and Fourier series

sin(3x) cos(3x) dx = 0. since sin(3x) cos(3x) is odd and the interval [ π, π] is symmetric about 0. Thus f (x) = sin(3x) and g(x) = cos(3x) are orthogonal on [ π, π]. Orthogonal collections: A collection of functions fφ0(x), φ1(x), . . . , φm(x), . . . g defined on [a, b] on [a, b] if Z. b. ................
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