W f(x) 1X df(x) X 202 f(xdx x sinx adx sinx dx SInx dx cosr COS 2 2 上一页下一页返回( ) df (x) x f x x  −       = 1 0 2 1 0 2 2 2 ( ) f (x)dx f x = −   1 0 2 2 2 1 dx x x x 2 1 0 2 2sin 2  = − x x dx  = − 1 0 2 sin   (cos1 1) 2 1 cos 2 1 sin 2 1 1 0 2 2 1 0 2 = − = = −  x dx x