问题
解答题
计算:
|
答案
+1 1+2
+1 1+2+3
+…+1 1+2+3+4 1 1+2+3+4+…+10
=
+2 2×(1+2)
+2 3×(1+3)
+…+2 4×(1+4) 2 10×(1+10)
=
-2 2
+2 3
-2 3
+2 4
-2 4
+…+2 5
-2 10 2 11
=1-2 11
=9 11
计算:
|
+1 1+2
+1 1+2+3
+…+1 1+2+3+4 1 1+2+3+4+…+10
=
+2 2×(1+2)
+2 3×(1+3)
+…+2 4×(1+4) 2 10×(1+10)
=
-2 2
+2 3
-2 3
+2 4
-2 4
+…+2 5
-2 10 2 11
=1-2 11
=9 11