ϑʔϦΤڃల։ͱ • 2 π पظؔΛ sin ͱ cos ʹղʢʹల։ʣ • Իॲཧɺը૾ॲཧʹར༻ • ϑʔϦΤมɺϑʔϦΤڃల։ͷ֦ு • पظؔͰͳͯ͘ల։Մೳ f(x) = a0 2 + 1 X k=1 (ak cos kx + bk sin kx) ak = 1 ⇡ Z ⇡ ⇡ f(x) cos kx dx bk = 1 ⇡ Z ⇡ ⇡ f(x) sin kx dx
f(x) = a0 2 + a1 cos 1x + b1 sin 1x + a2 cos 2x + b2 sin 2x + a3 cos 3x + b3 sin 3x + a4 cos 4x + b4 sin 4x + a5 cos 5x + b5 sin 5x + a6 cos 6x + b6 sin 6x + a7 cos 7x + b7 sin 7x + a7 cos 7x + b7 sin 7x
f(x) = a0 2 + 1 X k=1 (ak cos kx + bk sin kx) ak = 1 ⇡ Z ⇡ ⇡ f(x) cos kx dx bk = 1 ⇡ Z ⇡ ⇡ f(x) sin kx dx =< f, cos kx > =< f, sin kx > =< f, cos kx > =< f, sin kx >