x*x-(2+m)x+2m=p*p-(2+m)p+2mx*x-p*p-(2+m)(x-p)=(x-p)(x+p-2-m)=0x1=p x2=2+m-p x1x2/2=(2p+mp-p*p)/2 (2+m>p) =-(p-(2+m)/2)(p-(2+m)/2)/2+(2+m)(2+m)/8当2p=2+m时Smax=(2+m)(2+m)/8
