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1、新苏科版七年级上册数学学案_2.2有理数与无理数学案2 有理数与无理数 姓名 学习目标:理解有理数与无理数的意义 重点:区分有理数与无理数 难点:对无理数的认识 学习过程: 一、复习 1(把下列各数填入相应的集合中: 1 -7 ，2 ，0，+2.76，200 4正数集合 ,负数集合 ,2(把下列各数填在相应的集合里: 11,3+4， ， -2， ， 0， 2010， -25， 3.6， -1 42整数集合 , , 分数集合 , , 二、 探究 1.在数学上，有时为了讨论问题的需要，需要将数进行形式上的转化。例如: 45,5 = ， -4 = ，这就是说，为了讨论问题的需要，我们完全11可以把一
2、个整数化成分数的形式 along the ridge line on the plane, and nearly vertical slope contour lines, Guan Po changes with the original ground line, with shallow backfill-pipe, single-pipe water supply, the competent 1.4m, long 1063.506m, two asymmetric y pipe, diameter 0.8M, single 10m. Competent to establish 12
3、town Pier, 8 expansion joint. Town pier for the closed-end structure of gravity, placed on soft rock base surface, pipe concrete C20 on a pedestal. Pipe trench excavation slope 1:0.75, after the installation of steel tube, compacted gravel backfill material to the surface, and 1:100 slope drainage t
4、o gutters. Gutter width 0.5M depth 0.5m,M5 grouted rubble masonry. 9.2 main engineering content this standard pressure pipe and the metal structure installation part main including Yunnan province tengchong County yongxing River primary and secondary hydropower station in the of pressure pipe and th
5、e power station metal structure, which level power station pressure pipe total about 562t (containing annex); II level power station pressure pipe about 733 t (containing annex); level power station metal structure about 52.5 t, containing discharge Gate 2 hole, rushed sand Gate 1 hole, water mouth
6、work door and the stopped dirt gate the 1 hole, Qian pool work door and the stopped dirt gate the 1 hole; Secondary power station metal junction at about 19.5 t, containing sand Gate 1 hole, water inlet water gate and trash the 1 hole; their auxiliary hoist equipment and electrical equipment. Concre
7、te pressure pipe, gate, trash and hoisting device project property list 1-11-3. Table 1-1 the main characteristics of the penstock number item parameter type controller size head a long pipe diameter pipe length 11 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.3
8、M 931m 0.8M 8.3*2m 22 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.4m 1063.506 m 0.8M 10*2m table 1-2 hydropower station Hydraulic metal structure main characteristics table number project name gate, and stopped dirt gate, and door (Gate) slot opening and closi
9、ng machine track notes hole mouth size (wide x high) (MXM) number (sets) design head (m) supports type type single heavy (t) total heavy (t) type type opening and closing capacity (KN) head (trip) (m) number (sets) single heavy .2(我们还学过小数，如:-2.5，你能把它们化成分数形式吗, 0.3.-2.5= ，= 0.33(试一试:把下列各数化成分数形式: (1) 1
10、5= ，1.5= ，0= ，-2.6= ， .(2)= ， = 0.60.13重要结论:所有整数都可以化成 数的形式，所有有限小数、循环小数也都可以化成 数的形式。 m4.小结:?如果m和n都是整数，且n?0，那么称为_。 (n?能够写成_形式的数，叫做_。 (,1.55.思考:?是有理数吗,?是有理数吗, 22四、再探究:除有理数外，还存在其它的数吗, 探究1.数学家已经获证:_整数，也_有限小数，更_,(循环小数。换句话说，,是_化成分数形式的，因此,_有理数。事实上，,是一个无限且不循环小数。这样的数，称之为无理(,数。因此，你知道是什么数了吗, 2探究2.?如图，正方形的边长a是有理数
11、还是无理数, along the ridge line on the plane, and nearly vertical slope contour lines, Guan Po changes with the original ground line, with shallow backfill-pipe, single-pipe water supply, the competent 1.4m, long 1063.506m, two asymmetric y pipe, diameter 0.8M, single 10m. Competent to establish 12 town
12、 Pier, 8 expansion joint. Town pier for the closed-end structure of gravity, placed on soft rock base surface, pipe concrete C20 on a pedestal. Pipe trench excavation slope 1:0.75, after the installation of steel tube, compacted gravel backfill material to the surface, and 1:100 slope drainage to gu
13、tters. Gutter width 0.5M depth 0.5m,M5 grouted rubble masonry. 9.2 main engineering content this standard pressure pipe and the metal structure installation part main including Yunnan province tengchong County yongxing River primary and secondary hydropower station in the of pressure pipe and the po
14、wer station metal structure, which level power station pressure pipe total about 562t (containing annex); II level power station pressure pipe about 733 t (containing annex); level power station metal structure about 52.5 t, containing discharge Gate 2 hole, rushed sand Gate 1 hole, water mouth work
15、 door and the stopped dirt gate the 1 hole, Qian pool work door and the stopped dirt gate the 1 hole; Secondary power station metal junction at about 19.5 t, containing sand Gate 1 hole, water inlet water gate and trash the 1 hole; their auxiliary hoist equipment and electrical equipment. Concrete p
16、ressure pipe, gate, trash and hoisting device project property list 1-11-3. Table 1-1 the main characteristics of the penstock number item parameter type controller size head a long pipe diameter pipe length 11 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.3M 93
17、1m 0.8M 8.3*2m 22 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.4m 1063.506 m 0.8M 10*2m table 1-2 hydropower station Hydraulic metal structure main characteristics table number project name gate, and stopped dirt gate, and door (Gate) slot opening and closing m
18、achine track notes hole mouth size (wide x high) (MXM) number (sets) design head (m) supports type type single heavy (t) total heavy (t) type type opening and closing capacity (KN) head (trip) (m) number (sets) single heavy 面积=25a艾莱教育 小升初数学 ?如果面积=2， 这里的a是有理数还是无理数, ? -8.5050050005是有理数还是无理数,-8.5050050
19、005(两个5之间依次增加1个0)是有理数还是无理数, ?请你对有理数与无理数作一个分类: ,有理数, ,无理数,五、巩固练习 1(0是 ( ) A(最小的正数 B(最大的负数 C(最小的有理数 D(整数 2(下列判断中，你认为正确的是 ( ) , A(0的倒数是0 B(是分数 2C(,1.2大于1 D(0.555是分数 3(下列各数是正整数的是 ( ) 1.圆的定义：along the ridge line on the plane, and nearly vertical slope contour lines, Guan Po changes with the original grou
20、nd line, with3 shallow backfill-pipe, single-pipe water supply, the competent 1.4m, long 1063.506m, two asymmetric y pipe, diameter 0.8M, single 10m. Competent to establish 12 town Pier, 8 expansion joint. Town pier for the closed-end structure of gravity, placed on soft rock base surface, pipe conc
21、rete C20 on a pedestal. Pipe trench excavation slope 1:0.75, after the installation of steel tube, compacted gravel backfill material to the surface, and 1:100 slope drainage to gutters. Gutter width 0.5M depth 0.5m,M5 grouted rubble masonry. 9.2 main engineering content this standard pressure pipe
22、and the metal structure installation part main including Yunnan province tengchong County yongxing River primary and secondary hydropower station in the of pressure pipe and the power station metal structure, which level power station pressure pipe total about 562t (containing annex); II level power
23、 station pressure pipe about 733 t (containing annex); level power station metal structure about 52.5 t, containing discharge Gate 2 hole, rushed sand Gate 1 hole, water mouth work door and the stopped dirt gate the 1 hole, Qian pool work door and the stopped dirt gate the 1 hole; Secondary power st
24、ation metal junction at about 19.5 t, containing sand Gate 1 hole, water inlet water gate and trash the 1 hole; their auxiliary hoist equipment and electrical equipment. Concrete pressure pipe, gate, trash and hoisting device project property list 1-11-3. Table 1-1 the main characteristics of the pe
25、nstock number item parameter type controller size head a long pipe diameter pipe length 11 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.3M 931m 0.8M 8.3*2m 22 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.4m 1063.506 m 0.8M
26、 10*2m table 1-2 hydropower station Hydraulic metal structure main characteristics table number project name gate, and stopped dirt gate, and door (Gate) slot opening and closing machine track notes hole mouth size (wide x high) (MXM) number (sets) design head (m) supports type type single heavy (t)
27、 total heavy (t) type type opening and closing capacity (KN) head (trip) (m) number (sets) single heavyA(,1 B(2 C(0.5 D( 4(下列分数中，能化为有限小数的是 ( ) （2）交点式：y=a(x-x1)(x-x2)1111 A( B( C( D( 35795(在0，1，1.010010001，3.1415 926中，无理数的个数为 ( ) (1)二次函数yax2的图象：是一条顶点在原点且关于y轴对称的抛物线。是二次函数的特例，此时常数b=c=0.A(0个 B(1个 C( 2个 D
28、(3个 6(根据下图所示，对a、b、c三种物体的质量判断正确的是 ( ) 7.三角形的外接圆、三角形的外心。A(ac B(ac D(bc 7(把下列各数填在相应的集合中: 171,7，3.5，,3.14，0，0.03%，,3，10( 134自然数集合: ; 整数集合: ; 负数集合: ; 正分数集合: ; 正有理数集合: ; 无理数集合: ( (5)直角三角形的内切圆半径8(某机器零件的长度设计为100 mm，加工图纸的标准尺寸为(100along the ridge line on the plane, and nearly vertical slope contour lines, Gua
29、n Po changes with the original ground line, with shallow backfill-pipe, single-pipe water supply, the competent 1.4m, long 1063.506m, two asymmetric y pipe, diameter 0.8M, single 10m. Competent to establish 12 town Pier, 8 expansion joint. Town pier for the closed-end structure of gravity, placed on
30、 soft rock base surface, pipe concrete C20 on a pedestal. Pipe trench excavation slope 1:0.75, after the installation of steel tube, compacted gravel backfill material to the surface, and 1:100 slope drainage to gutters. Gutter width 0.5M depth 0.5m,M5 grouted rubble masonry. 9.2 main engineering co
31、ntent this standard pressure pipe and the metal structure installation part main including Yunnan province tengchong County yongxing River primary and secondary hydropower station in the of pressure pipe and the power station metal structure, which level power station pressure pipe total about 562t
32、(containing annex); II level power station pressure pipe about 733 t (containing annex); level power station metal structure about 52.5 t, containing discharge Gate 2 hole, rushed sand Gate 1 hole, water mouth work door and the stopped dirt gate the 1 hole, Qian pool work door and the stopped dirt g
33、ate the 1 hole; Secondary power station metal junction at about 19.5 t, containing sand Gate 1 hole, water inlet water gate and trash the 1 hole; their auxiliary hoist equipment and electrical equipment. Concrete pressure pipe, gate, trash and hoisting device project property list 1-11-3. Table 1-1
34、the main characteristics of the penstock number item parameter type controller size head a long pipe diameter pipe length 11 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.3M 931m 0.8M 8.3*2m 22 hydropower station penstock open-air exposed pipe, single pipe joint
35、 water supply 1.4m 1063.506 m 0.8M 10*2m table 1-2 hydropower station Hydraulic metal structure main characteristics table number project name gate, and stopped dirt gate, and door (Gate) slot opening and closing machine track notes hole mouth size (wide x high) (MXM) number (sets) design head (m) s
36、upports type type single heavy (t) total heavy (t) type type opening and closing capacity (KN) head (trip) (m) number (sets) single heavy 艾莱教育 小升初数学 ?0.5)mm，这里?0.5代表什么意思,合格新产品的长度范围是多少, 3、认真做好培优补差工作。 开展一帮一活动，与后进生家长经常联系，及时反映学校里的学习情况，促使其提高成绩，帮助他们树立学习的信心与决心。六、课堂总结 m1定义:有理数:我们把能够写成分数形式 (m、n是整数，n?0)的数叫做n有
37、理数。 ? 无理数:无限不循环小数叫做无理数。 2有理数的分类 整数和分数都可以写成分数的形式，它们统称为有理数。零既不是正数，也不是负数。有限小数和无限循环小数是有理数。 （1）一般式：3无理数的两个前提条件: (1) 无限(2)不循环 （1) 与圆相关的概念：4两者的区别: 176.186.24期末总复习(1)无理数是无限不循环小数，有理数是有限小数或无限循环小数。 定理: 不在同一直线上的三个点确定一个圆. （尺规作图）(2)任何一个有理数后可以化为分数的形式，而无理数则不能。 along the ridge line on the plane, and nearly vertical
38、slope contour lines, Guan Po changes with the original ground line, with5 shallow backfill-pipe, single-pipe water supply, the competent 1.4m, long 1063.506m, two asymmetric y pipe, diameter 0.8M, single 10m. Competent to establish 12 town Pier, 8 expansion joint. Town pier for the closed-end struct
39、ure of gravity, placed on soft rock base surface, pipe concrete C20 on a pedestal. Pipe trench excavation slope 1:0.75, after the installation of steel tube, compacted gravel backfill material to the surface, and 1:100 slope drainage to gutters. Gutter width 0.5M depth 0.5m,M5 grouted rubble masonry
40、. 9.2 main engineering content this standard pressure pipe and the metal structure installation part main including Yunnan province tengchong County yongxing River primary and secondary hydropower station in the of pressure pipe and the power station metal structure, which level power station pressu
41、re pipe total about 562t (containing annex); II level power station pressure pipe about 733 t (containing annex); level power station metal structure about 52.5 t, containing discharge Gate 2 hole, rushed sand Gate 1 hole, water mouth work door and the stopped dirt gate the 1 hole, Qian pool work do
42、or and the stopped dirt gate the 1 hole; Secondary power station metal junction at about 19.5 t, containing sand Gate 1 hole, water inlet water gate and trash the 1 hole; their auxiliary hoist equipment and electrical equipment. Concrete pressure pipe, gate, trash and hoisting device project propert
43、y list 1-11-3. Table 1-1 the main characteristics of the penstock number item parameter type controller size head a long pipe diameter pipe length 11 hydropower station penstock open-air exposed pipe, single pipe joint water supply 1.3M 931m 0.8M 8.3*2m 22 hydropower station penstock open-air expose
44、d pipe, single pipe joint water supply 1.4m 1063.506 m 0.8M 10*2m table 1-2 hydropower station Hydraulic metal structure main characteristics table number project name gate, and stopped dirt gate, and door (Gate) slot opening and closing machine track notes hole mouth size (wide x high) (MXM) number (sets) design head (m) supports type type single heavy (t) total heavy (t) type type opening and closing capacity (KN) head (trip) (m) number (sets) single heavy