222)(21)(xex,0),(N),(N2,DE）曲线在）曲线在x x轴上方，并且关于直线轴上方，并且关于直线x=x=对称；对称； )(x2221)(xex) 1 , 0( N0 x)(0 x0 x)(0 x)(0 x)(0 xxP)(xF)(x),(N) 1 , 0( N)()()(abbxaPabxyxbyaxnxyxnyxbniiniii2121niixnx11)()(21221211ynyxnxyxnyxrniiniiniiiCdC)5 . 0 ,(2dN 90d8980d，) 1 , 0( N9772. 0)2()2(P则01. 0)327. 2()327. 2(P89)5 . 0 ,(dN)327. 2(),2(p.99. 0dp解).1 , 0(),1 , 0(NN则)(xf0 x)(xf0 x)(xf)(100, 2(cmNcm8; 6 ,5 .15, 5 .12;16,5 .18, 5 .15;18,5 .21, 5 .18;22,5 .24, 5 .21;20,5 .27, 5 .24;10,5 .30, 5 .278 ,5 .33, 5 .30
