(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:93 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:
Desired Domain Name Taken? Here’s What To Do Next  Sex Bloggers Shocked By Tumblr’s Smut Smackdown  Can You Recover From A Facebook Rant Gone Viral?  Blogging On A Schedule: Why Providing Consistent Content Matters  Blogger Tricks Google Into Thinking He Is ‘Sexiest Man In Britai  Popular “Mommy Blogger” Calls It Quits, Criticizes Blogging Worl  Blogging in the Viral Age: 5 Ways to Tip the Scales in Your Favo  Why You Need To Update Your Jetpack Plug-In Right Now  7 Online Marketing Tools You Need to Master in 2016  How to Compute the Min Cost of Climbing Stairs via Dynamic Progr 
评论列表
添加评论