A.4 | B.5 | C.6 | D.7 |
1 |
1×2 |
1 |
2×3 |
1 |
i(i+1) |
1 |
i+1 |
i |
i+1 |
5 |
6 |
i |
i+1 |
5 |
6 |
A.2010×22012+2 | B.2011×22011-2 |
C.2010×22011+2 | D.2011×22012-2 |
2009 |
2010 |
A.-1 | B.1 | C.-2 | D.2 |
|
A.①y=0;②x=0;③y=1 | B.①y=0;②x<0;③y=1 |
C.①-1;②x>0;③y=0 | D.①y=-1;②x=0;③y=0 |
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