用归纳方法把有限小数与无限循环小数化成分数MICROSOFTOFFICEWORD文档
#用归归方法把有限小无限循归小化成分,数与数数
如何把循归小数 ;归循归小、混循归小、,有限小、归小化成数数数数分数 ,1、有感于小数 0.126与0.?126?二者之归的归差~归差是多少, 突数异数异
归“奇想”、“想天归”,异
令0.126=126/1000
=126/;999+1,
假归,0.126=126/1000=126/;999+1,=[;126/999,+X]
=;0.?126?+X,;——1,式~
移归、通分得,
126/1000=126/;999+1,=[;126/999,+X]X=(126/1000)-;126/999,
X=;126*999,/;1000*999,-;126*1000,/;999*1000,
X =(125874/999000)-(126000/999000)=-126/999000
X=-126/999000
=-0.000?126?~
0.126=126/1000与0.?126?=126/999的归差是,数异
-0.000?126?=-126/999000~
把X=-0.000?126?=-126/999000~
并代入;1,式得,;126/999,-;126/999000,=126/1000=0.126
因归0.?126?=126/999
所以 ;0.?126?-0.000?126?,
=0.126~通归归算后正~确
同归我归归得到了:
126/999=0.?126?、0.?126?=126/999、-0.?126?=-126/999
-0.000?126?=-
126/999000、0.000?126?=126/999000~0.126=126/1000
2、由上述同理可得,0.?126?
=126/999
=126/;1000-1,
令,126/;1000-1,=[;126/1000,+X]
假归,126/999=[;126/1000,+X] ——;2,式~
或,0.?126?=;0.126+X,
移归、通分得,
126/;1000-1,=[;126/1000,+X]~
即,126/999=[;126/1000,+X]
X=(126×1000)/(999×1000)-(126×999)/(1000×999)X =(126000/999000)- (125874/999000)=126/999000
X=126/999000=0.000?126?~
X=126/999000
=0.000?126?~
0.?126?=126/999与0.126=126/1000的归差是,数异
0.000?126?=126/999000~
并把X=126/999000=0.000?126?
代入126/999=[;126/1000,+X] ——;2,式~
126/999=[;126/1000,+126/999000] ——;2,式~
126/999=[;126/1000,+126/999000]= 0.?126?通归归归后正~确
同归归得到了,
0.?126?=126/999~0.000?126?=126/999000~0.126=126/1000
注,字左右上方归点的小均表示无限循归小~数数数
譬如,
1415926/10000000=0.1415926~
=1415926/;9999999+1,~
假归,1415926/10000000=[1415926/;9999999,+X]=;0.?1415926?+X,;——1式,
所以X= [;1415926*9999999,/10000000*9999999]-;1415926*10000000,/;9999999*10000000,
=;144/99999990000000,-;140/99999990000000,=-1415926/99999990000000
=-0.0000000?1415926?;特表示无限循归小,数
X=-0.0000000?1415926?归入;1式,归归正~确
同归归得到了,
0.1415926=1415926/10000000~0.?1415926?=1415926/9999999~0.0000000?1415926?=1415926/99999990000000
根据以上算归果由此归归归,任一;无限,循归小都可以化成分~归运数数
循归小化成分后的分子就是一循归归的字所归成的~分母各位数数个数数
数字都是9~其一循归归位相同~混循归小化成分的分子个数与个数数数
就是第2循归归前面的字~分母的归位字是个数几数9~末位是几0~9的个数与个数一循归归位相同~0的不循归归的部分位相同~归归归个数与数称
归方法~由于上述有限小、无限循归小化归分比归归归直归~混循归小数数数
数数况化成分归有一归情比归归归,
3、把混循归小化成分;比归归归、有点归度,,数数
譬如,把混循归小数0.228?
化归分,数
解,0.228?
=[;228/1000,+8/9000,]
=228/;900+100,+8/9000
=[;228/900,-;228/9000,]+;8/9000,=;228/900,+[;8/9000,-;228/9000,]=;228/900,-;22/900,
=;228-22,/900
=206/900
=103/450
=0.228?~
譬如,把混循归小数0.126?化成分,数
解,0.126?=;0.126+0.0006?,
=;126/1000,+;6/9000,
=[126/;900+100,+;6/9000,]
=[126/1000+;6/9000,]
=[;126/900,-;126,/;9000,]+;6/9000,=;126/900,+[;6/9000,-;126/9000,]=;126/900,-;12/900,
=;126-12,/900
=114/900
=57/450
=0.126?~
譬如,把混循归小数0.123?68?化成分,数
解,0.123?68?=(0.12368+0.00000?68?)=(12368/100000)+;68/9900000,
=[;12368/99000,-;12368/990000,]+;68/9900000,
=;12368/99000,+[;68/9900000,-;12368/9900000,]
=;12368/99000,+[;68/9900000,-;12368/9900000,]
=;12368/99000,-;12300/9900000,=(12368-123)/99000
=12245/99000
=2449/19800~
其他混循归小依次归推~数
归明,上式中的0.228?表示0.228888...~0.126?表示0.126666...,0.123?68?混循归小~把以上算特征归归归,数运混循归小化成数分的分子就是第数2循归归前面的字归成的去不循归部分字归成个数数减数
的之差~分母的归位字是数几数9~末位是几0~9的一循归归个数与个位相同~数0的不循归归的部分位相同个数与数, 归归归归方法~譬如,称
0.228?=;228-22,/900=206/900=103/450、0.126?=;126-12,/900=114/900=57/450,0.123?68?=(12368-
123)/99000
=12245/99000=2449/19800~能归分的要化归。
4、有限小化成分,数数分母的首位是数1后面是0~0的小位个数与数数
的相同~分子是把有限小取作整~把小点右归的看作整作归分个数数数数数数
子~但不包括小点右归十分位、百分位、千分位~数...上的0~能归分的要化归~
譬如,将0.678化归分~数即
678/1000=339/500~0.1681=1681/10000~0.087=87/1000~0.0078=78/10000=39/5000~...~
5、归小;混小,化成分,数数数
譬如,将2.18化成分~解,因归数2.18=2+0.18~所以~
2.18=2+0.18=2+;18/100,=2+;9/50,=109/50~把3.1415化成分~数
?3.1415=3+0.1415~?3.1415=3+;1415/10000,=3+;283/2000,=6283/2000~等等以此归推~能归分的一定要化归~
6、归小化成分其法归、方法以上相同,数数与
譬如,-0. ?186?=-186/999=-62/333~-0.0?87?=-87/990=-29/330~-0.5678=-5678/10000=-2839/5000~等等依次归推~能归分的一定要化归最归分数~...。
7、使用归归方法把下列小化成分,数数
;1,0.368?616?~;2,0.0105?717?~;3,0. ?18?~0.
?168?,0. ?1787?,(4)0.0?869?,0.00?716?,
(5)0.36767~0.66558698~0.0687~0.0065~(6)2.18~3.1415~3. ?56?解,
;1,0.368?616?=;368616-
368,/999000=368248/999000=46031/124875~
;2,0.0105?717?=;105717-
105,/9990000=105612/9990000=8801/832500~
;3,0. ?18?=18/99=2/11~0. ?168?=168/999=56/333~0. ?1787?=1787/9999~
(4)0.0?869?=869/9990~0.00?716?=716/99900=179/24975~(5)0.36767=36767/10000~0.66558698=66558698/100000000=33279349/50000000~0.0687=687/10000~0.0065=65/10000=13/2000~
(6)2.18=109/50~3.1415=6283/2000~3.
?54?=3+;54/99,=3+;6/11,=39/11。
以上容~非猜归~是由分母算大法归公式;公式有列出,所得到内并拆运没
的~...。;归归~所归免,个
;作者,奇归~归位,归归,
归展归归,
•1
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