f(=-(sin at-osin 3at +o- sin 5 A A f()=---(sn2ot+sn4ot+sn6ot+……) )4A(1 cos 4ot cos6ot-… 2A1丌 (a)2A/snm、1 sin 2ot +-sin 30t f()8 7 (cos at +-cos 3t +cos 5ot (sin at +sn 3at +=sn Sat 8 f(t)=A[( T/2 93求图95所示各非正弦周期信号的直流分量A0。130 2 sin 5 ) 25 1 sin 3 9 1 (sin 8 ( ) = 2 t − t + t − A f t     3 sin 6 ) 3 1 sin 4 2 1 (sin 2 2 ( ) = − t + t + t + A A f t     4 cos6 ) 35 1 cos 4 15 1 cos 2 3 1 2 1 ( 4 ( ) = − t − t − t − A f t     5 cos 4 ) 15 1 cos 2 3 1 sin 2 4 1 ( 2 ( ) = + t − t − t − A f t      6 sin 3 ) 3 1 sin 2 2 1 (sin 2 ( ) = t − t + t − A f t     7 cos5 ) 25 1 cos3 9 1 (cos 8 ( ) = 2 t + t + t + A f t     8 sin 5 ) 5 1 sin 3 3 1 (sin 2 2 1 f (t) = A[( + t + t + t +  9.3 求图 9.5 所示各非正弦周期信号的直流分量 A0。 f(t) t T 0 T/2 A f(t) t T 0 T/2 A f(t) t T 0 T/2 A f(t) t T 0 T/2 A f(t) t T 0 T/2 A f(t) t T 0 T/2 A f(t) t T 0 T/2 A