A.真;∃x0∈R,x02-x0+1>0 | B.假;∃x0∈R,x02-x0+1>0 |
C.真;∀x∈R,x2-x+1>0 | D.假;∀x∈R,x2-x+1>0 |
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A.命题“Ex∈R,使得x2+x+1<0”的否定是:“∀x∈R,均有x2+x+1≥0” | ||||||||
B.命题“若x2=1,则x=1”的否命题为:“若x2=1,则x≠1” | ||||||||
C.设A、B为两个定点,k为非零常数,|
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D.命题:“过定圆C上一定点A作圆的动弦AB,设O为坐标原点,若
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A.∀x∈R,p | B.∀x∈R,x3-x2+1>0 |
C.∃x∈R,x3-x2+1≤0 | D.∃x∈R,x3-x2+1<0 |
A.
| B.1 | C.
| D.2 |
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