作业帮有人可以给我解释一下RATIONAL 和IRRATIONAL NUMBER的区别吗rational number and irrational number
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有人可以给我解释一下RATIONAL 和IRRATIONAL NUMBER的区别吗
rational number and irrational number
有理数和无理数
有理数（rational number)：能精确地表示为两个整数之比的数．
如3,-98.11,5.72727272……,7/22都是有理数．
整数和通常所说的分数都是有理数．有理数还可以划分为正有理数,0和负有理数．
无理数指无限不循环小数 如：π
有理数和无理数的区别
只要有循环节便都可化为分数,自然便是有理数.
我曾经推理过把推理过把循环小数化为分数的方法,且看这个规律：
0.1111...＝1/9
0.121212...＝12/99＝4/33
0.123123123...＝123/999＝41/333
0.142857142857142857...＝142857/999999＝1/7
所以如果循环节是从第一位小数开始的,如循环节x有n位,则此数＝x/(10^n-1)
如果不是,也可以化为分数：
1.05555...＝1+5/90＝19/18
0.32010101...＝32/100+1/9900＝3169/9900
0.999...＝9/9＝1
所以即使循环节有百亿兆位也是可以化为分数的,也是有理数；而无理数不论顺到多少位也找不出循环节来.
Rational numbers are those can be expressed as a/b, where a and b are integers. Examples are: all integers, fractions, terminating decimals, or repeating non-terminating decimals (eg. 0.333333...= 1/3...
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Rational numbers are those can be expressed as a/b, where a and b are integers. Examples are: all integers, fractions, terminating decimals, or repeating non-terminating decimals (eg. 0.333333...= 1/3) But irrational numbers are those cannot be expressed as a/b, such as square root 2, which are non-terminating and non-repeating decimals.
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有理数、无理数