例5设y=sinx,求y 解卩=c0sx=sin(x+ 2 y"=cs(x+)=sim(x+行+)=sim(x+2死 22 y=c0s(x+2. =sin(x+3.2 y=sin(x+n π—2 同理可得(cosx)(")=cos(x+n 2例5 sin , . (n) 设 y = x 求y 解 y = cos x ) 2 sin(  = x + ) 2 cos(  y = x + ) 2 2 sin(  +  = x + ) 2 sin( 2  = x +  ) 2 cos( 2  y = x +  ) 2 sin( 3  = x +   ) 2 sin( ( )  y = x + n n 同理可得 ) 2 (cos ) cos( ( )  x = x + n n