Question

已知二次函数y=x的平方-2x-1,若A(m,y1),B(m+1,y2)两点都在图像上,比较y1和y2

Answer 1

y1=m^2-2m-1

y2=(m+1)^2-2(m+1)-1

=m^2+2m+1-2m-2-1

=m^2-2

y2-y1=(m^2-2)-(m^2-2m-1)

=2m-1

当 m>1/2 时,y2-y1>0,y2>y1

当 m=1/2 时,y2-y1=0,y2=y1

当 m