求解两道七年级简算题

来源:百度知道 编辑:UC知道 时间:2024/05/25 18:26:33
1.

(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)/ 2^32— 1 的值是多少?
2.

1/23,303/2323,50505/232323,7070707/23232323,909090909/2323232323,

这几个数相加的和是多少?
^ 表示几次方,如2^3=8.
/ 表示分数线。

谢谢各位!!!

哦,第一题的分数线下面你忘加括号了……

(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)/ (2^32— 1)
=(2-1)(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)/ (2^32— 1)
=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)/ (2^32— 1)
……
=(2^32-1)/(2^32-1)
=1

1/23+303/2323+50505/232323+7070707/23232323+909090909/232323232323
303=101×3,2323=101×23
50505=10101×5,232323=10101×23
7070707=1010101×7,23232323=1010101×23
909090909=101010101×9,2323232323=101010101×23
故,1/23+3/23+5/23+7/23+9/23=25/23

(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)/( 2^32- 1)
=(2-1)(2+1)(2^2+1)...(2^16+1)/(2^32-1)
=(2^2-1)(2^2+1)...(2^16+1)/(2^32-1)
=(2^4-1)...(2^16+1)/(2^32-1)
=(2^32-1)/(2^32-1)
=1.

303/2323=(3*101)/(23*101)=3/23.
50505/232323=(5*10101)/(23*10101)=5/23.
7070707/23232323=7/23.
909090909/2323232323=9/23.
这几个数相加的和=1/23+3/23+5/23+7/23+9/23=25/23.