=2lsint2=2 例3设f(x)=t,求x(x sinx 解( 1x/=22 2x= X f(0-=「 sin t dt=0 ↓(=//x2 上一页下一页返回2sin  2 2 = 0 =  t 例 3 设 ( ) dt ， 求 . t t f x x  = 2 1 sin xf (x)dx  10 解 ( ) x x x x x f x 2 2 2 2sin 2 sin  =  = ( ) 0 sin 1 11 = =  dt t t f ( ) ( )   =   22 10 10 x xf x dx f x d