计算:1+31/6+51/12+71/20+91/30+111/42+131/56+151/72+171/90.

问题描述:

计算:1+3

1
6
+5
1
12
+7
1
20
+9
1
30
+11
1
42
+13
1
56
+15
1
72
+17
1
90

1+3

1
6
+5
1
12
+7
1
20
+9
1
30
+11
1
42
+13
1
56
+15
1
72
+17
1
90

=1+(3+
1
6
)+(5+
1
12
)+(7+
1
20
)+(9+
1
30
)+(11+
1
42
)+(13+
1
56
)+(15+
1
72
)+(17+
1
90
),
=(1+3+5+7+9+11+13+15+17)+(
1
6
+
1
12
+
1
20
+
1
30
+
1
42
+
1
56
+
1
72
+
1
90
),
=81+
2
5

=81
2
5