问题
解答题
|
答案
+1 2×5
+1 5×8
+…+1 8×11
+1 2006×2009 1 2009×2012
=
×(1 3
-1 2
+1 5
-1 5
+1 8
-1 8
+…+1 11
-1 2006
+1 2009
-1 2009
)1 2012
=
×(1 3
-1 2
)1 2012
=
×1 3 1005 2012
=
.335 2012
|
+1 2×5
+1 5×8
+…+1 8×11
+1 2006×2009 1 2009×2012
=
×(1 3
-1 2
+1 5
-1 5
+1 8
-1 8
+…+1 11
-1 2006
+1 2009
-1 2009
)1 2012
=
×(1 3
-1 2
)1 2012
=
×1 3 1005 2012
=
.335 2012