1-2/3-2/9-2/27-2/81-2/243-2/729=_.
问题描述:
1-
-2 3
-2 9
-2 27
-2 81
-2 243
=______. 2 729
答
1-
-2 3
-2 9
-2 27
-2 81
-2 243
,2 729
=1-(
+2 3
+2 9
+2 27
+2 81
+2 243
),2 729
=1-(1-
+1 3
-1 3
+1 9
-1 9
+1 27
-1 27
+1 81
-1 81
+1 243
-1 243
),1 729
=1-(1-
),1 729
=1-1+
,1 729
=
1 729