5>式减去<6》式再除2,可得: f2(x)=q(x) La x y(ada 2 f1(x+a)=(x+a) x+at y(a)da+ f,(x-at)=o(x-at) 2a y(ada+<5>式减去<6>式再除2，可得： 2 ( ) 2 1 ( ) 2 1 ( ) 0 2 C d a f x x x x = - - ò j y a a 2 ( ) 2 1 ( ) 2 1 ( ) 0 1 C d a f x at x at x at x + + \ + = + ò + y a a j 2 ( ) 2 1 ( ) 2 1 ( ) 0 2 C d a f x at x at x at x + + - = - ò - y a a j