△=(2-m)^2-4(1+m)
=4-4m+m^2-4-4m
=m^2-8m≥0
m(m-8)≥0
m≤0 或m≥8
x1^2+x2^2=(x1+x2)^2-2x1x2=(m-2)^2-2(1+m)
=m^2-4m+4-2-2m
=m^2-6m+2
=(m-3)^2-7
当m=0时
x1²+x2²最小值为2
△=(2-m)^2-4(1+m)
=4-4m+m^2-4-4m
=m^2-8m≥0
m(m-8)≥0
m≤0 或m≥8
x1^2+x2^2=(x1+x2)^2-2x1x2=(m-2)^2-2(1+m)
=m^2-4m+4-2-2m
=m^2-6m+2
=(m-3)^2-7
当m=0时
x1²+x2²最小值为2