x | 20 |
A.∃x0∈R,x02-1≥0 | B.∀x∈R,x2-1<0 |
C.∃x0∈R,x02-1>0 | D.∀x∈R,x2-1≥0 |
x | 20 |
x | 20 |
A.若a>-3,则a≤-6 | B.若a≤-3,则a<-6 |
C.若a≤-3,则a≤-6 | D.若a≥-3,则a≤-6 |
A.∀a>0,b>0,a2+b2+2ab=(a+b)2 |
B.∀a,b∈R,a2+b2+2ab=(a+b)2 |
C.∃a<0,b>0,a2+b2+2ab=(a+b)2 |
D.∃a,b∈R,a2+b2+2ab=(a+b)2 |
A.对任意的a∈R,都有a2-2a+1<0 | ||
B.菱形的两条对角线相等 | ||
C.∃x,
| ||
D.对数函数在其定义域上是单调函数 |
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