内容正文:
同底数幂的除法
知识回顾
3.计算:
(1) 279÷97÷3
(2) b2m÷bm-1(m是大于1的整数)
(3) (-mn)9÷(mn)4
(4) (a-b)6÷(b-a)3÷(a-b)2
am÷an= (a≠0, m、n都是正整数,且m>n)
同底数幂相除,底数____, 指数___.
不变
相减
am–n
解:(1) 279÷97÷3
am÷an=am–n
解: (2) b2m÷bm-1
=327÷314÷3
=327-14-3
=310
= b2m-m+1
= bm+1
279
=(33)9
=327
am÷an=am–n
解(3) (-mn)9÷(mn)4
解(4) (a-b)6÷(b-a)3÷(a-b)2
=-(mn)9÷(mn)4
=-(mn)5
=-m5n5
=(a-b)6÷[-(a-b)]3÷(a-b)2
=-(a-b)
=b-a
PPT模板:www.1ppt.com/moban/ PPT素材:www.1ppt.com/sucai/
PPT背景:www.1ppt.com/beijing/ PPT图表:www.1ppt.com/tubiao/
PPT下载:www.1ppt.com/xiazai/ PPT教程: www.1ppt.com/powerpoint/
资料下载:www.1ppt.com/ziliao/ 范文下载:www.1ppt.com/fanwen/
试卷下载:www.1ppt.com/shiti/ 教案下载:www.1ppt.com/jiaoan/
PPT论坛:www.1ppt.cn PPT课件:www.1ppt.com/kejian/
语文课件:www.1ppt.com/kejian/yuwen/ 数学课件:www.1ppt.com/kejian/shuxue/
英语课件:www.1ppt.com/kejian/yingyu/ 美术课件:www.1ppt.com/kejian/meishu/
科学课件:www.1ppt.com/kejian/kexue/ 物理课件:www.1ppt.com/kejian/wuli/
化学课件:www.1ppt.com/kejian/huaxue/ 生物课件:www.1ppt.com/kejian/shengwu/
地理课件:www.1ppt.com/kejian/dili/ 历史课件:www.1ppt.com/kejian/lishi/
4
2、已知:am=5,an=4,求a 3m-2n的值。
解:
(1) 53÷53=___
(3) a2÷a2=
1
合作学习
(2) (-3)3÷(-3)3=
1
1
(a≠0)
讨论下列问题:
(1) 要使53÷53=53-3也能成立,你认为
应当规定50等于多少?80呢?
(3) 任何数的零次幂都可以规定等于1吗?
(2) 要使(-5)3÷(-5)3=(-5)3-3也能成立,你认为应当规定50等于多少?(-8)0呢?
任何不等于零的数
的零次幂都等于1.
a0=1
(a≠0)
规定:
例1
计算:
解:
例1
计算:
解:
例1
计算:
解:
判断:下列计算对吗?为什么?错的请改正。
(1)(-7)0= -1
(2 )(-1)0=-1
(3) 00=1
(2) a2÷a5=
合作学习
1
a( )
(1) 33÷35= = =
35
33
( )
1
1
3( )
3×3
2
3
(a≠0)
PPT模板:www.1ppt.com/moban/ PPT素材:www.1ppt.com/sucai/
PPT背景:www.1ppt.com/beijing/ PPT图表:www.1ppt.com/tubiao/
PPT下载:www.1ppt.com/xiazai/ PPT教程: www.1ppt.com/powerpoint/
资料下载:www.1ppt.com/ziliao/