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