(1/6+1/7+1/8)×(1/7+1/8+1/9)-(1/6+1/7+1/8+1/9)×(1/7+1/8)
- 时间:2020-06-13 17:16:40
- 分类:数学世界
- 阅读:155 次
“神马都是浮云”同学问:(1/6+1/7+1/8)×(1/7+1/8+1/9)-(1/6+1/7+1/8+1/9)×(1/7+1/8)怎么计算?第二种问法,请问一下各位:(6分之1+7分之1+8分之1)*(7分之1+8分之1+9分之1)—(6分之1+7分之1+8分之1+9分之1)*(7分之1+8分之1)这道算式等于多少啊?应该有简便算法吧!有老师能告诉我方法吗?
数学题解答:此题算式较长,其中有些部分为几个分数相加,且多次出现,故可以用换元法来解决。设1/6+1/7+1/8=a,则原式变成:
=(1/7+1/8+1/9)a-(a+1/9)×(1/7+1/8)
=(1/7+1/8+1/9)a-(1/7+1/8)a-(1/7+1/8)×1/9
=1/9a-(1/7+1/8)×1/9
此时再将a换回,变成1/6+1/7+1/8,这样算式又变成了:
=(1/6+1/7+1/8)×1/9-(1/7+1/8)×1/9
=1/6×1/9
=1/54
至此,已算出得数,主要用了换元法和乘法分配律解决了这个问题。
推荐阅读:The Importance of SEO and How They Improve the Number of Your Cl Learn The Basics Of Google My Business Iterative and Recursion Algorithms to Compute the Number of Step How to Check if a DLL or EXE is 32-bit or 64-bit (x86 or x64) us C++: How to Iterate the Elements over the Sets (set, unordered_s How to Iterate over the Items in Java’s Map (HashMap, Hash Dynamic Programming Algorithm to Count Vowels Permutation Exploring the Importance of Brand Consistency Cleaning A WordPress Malware Infection For Dummies 7 Killer Ways to Higher Average Time on Page
- 评论列表
-
- 添加评论