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

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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

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
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

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
x1=√2/2,x2=-√2/2
所以x1+x2=0,x1x2=-1/2
应选C