若方程2x2=1的两实数根为x1、x2,则(  ) A.x1+x2=0且x1x2=1 B.x1+x2=1且x1x2=0 C.x1+x2=0且x1x2=-12 D.x1+x2=0且x1x2=12

问题描述:

若方程2x2=1的两实数根为x1x2,则(  )
A. x1+x2=0且x1x2=1
B. x1+x2=1且x1x2=0
C. x1+x2=0且x1x2=-

1
2

D. x1+x2=0且x1x2=
1
2

解;方程2x2=1的两实数根为x1x2,方程可化为:2x2-1=0,
∴x1+x2=0且x1x2=-

1
2

故选C.