F.5 maths
2011-07-12 6:35 am
A binary number has n digits and all digits are ' 1 ' s . Convert the number into a decimal number in terms of n .
回答 (2)
2011-07-12 7:39 am
✔ 最佳答案
Decimal number= 1 + 1x2 + 1x2^2 + 1x2^3 + ..... 1x2^n
It is the sum of a G.P. in which:
The first term, a = 1
The common ratio, r = 2
The number of terms = n
Hence, decimal number
= a[(r^n) - 1]/(r - 1)
= 1[(2^n) - 1]/(2 - 1)
= (2^n) - 1
參考: 賣女孩的火柴
2011-07-12 7:44 am
Decimal number
= 1 + 1x2 + 1x2^2 + 1x2^3 + ..... + 1x2^(n-1)
= 1 + 1x2 + 1x2^2 + 1x2^3 + ..... + 1x2^(n-1)
收錄日期: 2021-04-13 18:05:03
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110711000051KK01262