.....e..243fx=11+x+11+a+axax+8x1a=8fx2a1fx2.......a=8fx=1+x1+x+13f（x）=1-x2x（1+x）^3x01]f（x）0x[1+f（x）0f（x）01][1+1fx2a0x0fx=fx=11+x+11+a+axax+8fx=fx=11+x+11+a+11+8axb=8axabx=8bfx1......IMO.....