多个同方向同频率简谐运动的合成 振幅相等，初相位依次差一个恒量 x(t)=A cos@t 合振动是简谐运动 x,(t)=A,c0s(ot+△p) x3(t)=A3c0s(ot+2△p) 0A1 x(t)=AN cos[@t+(N-1)Ao] sin(NΔp/2) A=A0 A=2Rsin(N△p/2) sin(△gp/2) A=2Rsin(△p/2) ⑩= N-1A0 2 x(t)=Acos(@t+)=Ao sin(NA/2) W-1 cos(@t+- sin(△o/2) 2 △0)二、多个同方向同频率简谐运动的合成 振幅相等，初相位依次差一个恒量 ( ) cos[ ( 1) ] ( ) cos( 2 ) ( ) cos( ) ( ) cos 3 3 2 2 1 1        = + −  = +  = +  = x t A t N x t A t x t A t x t A t N N  A1 A2 A3 A O x Q P     合振动是简谐运动 A = 2Rsin(N / 2) 2 sin( / 2) A0 = R  sin( / 2) sin( / 2) 0     = N A A   − = 2 N 1 ) 2 1 cos( sin( / 2) sin( / 2) 0      − +   = N t N x(t) = Acos(t +) A