12+14+18+116+132+164+1128+1256+1512+11024+12048+14096=______.
问题描述:
+1 2
+1 4
+1 8
+1 16
+1 32
+1 64
+1 128
+1 256
+1 512
+1 1024
+1 2048
=______. 1 4096
答
+1 2
+1 4
+1 8
+1 16
+1 32
+1 64
+1 128
+1 256
+1 512
+1 1024
+1 2048
1 4096
=1-
+1 2
-1 2
+1 4
-1 4
+…+1 8
-1 2048
1 4096
=1-
1 4096
=
4095 4096
故答案为:
.4095 4096
答案解析:通过观察,发现从第二项起,每个分数都是前一个分数的
,因此可把每个分数拆成两个分数相减的形式,然后通过加减相互抵消,解决问题.1 2
考试点:分数的巧算.
知识点:此题采用了裂项消项法,先进行分数裂项,然后通过加减相互抵消,求出结果.