A.∃x∈R,x+1>x | B.∃x∈Z,x2=2 | C.∀x∈R,x2>0 | D.∀x∈Z,x2>x |
2 |
A.∃x∈Z,使x2+2x+m>0 |
B.∀x∈Z,都有x2+2x+m>0 |
C.∀x∈Z,都有x2+2x+m≤0 |
D.不存在x∈Z,使x2+2x+m>0 |
A.∀x2>1,x≤1 | B.∀x2≤1,x≤1 | C.∃x2>1,x≤1 | D.∃x2≤1,x≤1 |
A.对∀x∈R,都有ex≥0 | B.对∀x∈R,都有ex>0 |
C.∃x0∈R,使得ex≥0 | D.对∀x∈R,都有ex<0 |
A.∃x∈R,x2+2x+2>0 | B.∃x∈R,x2+2x+2≥0 |
C.∀x∈R,x2+2x+2>0 | D.∀x∈R,x2+2x+2≤0 |
A.∃x∈[0,
| B.∃x∈(3,+∞),x2≤2x+1 | ||
C.∃x∈R,x2+x=-1 | D.∀x∈(0,
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