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初中数学《角的平分线性质的证明》教案

一、教学目标

【知识与技能】了解角的平分线的性质,能利用三角形全等证明角的平分线的性质,会利用角的平分线的性质进行证明与计算。

【过程与方法】在探究作角的平分线的方法及角的平分线的性质的过程中,进一步发展学生的推理证明意识和能力。

【情感态度与价值观】在主动参与数学活动的过程中,增强探究问题的兴趣、有合作交流的意识、动手操作的能力与探索精神,获得解决问题的成功体验。

二、教学重难点

【重点】角的平分线的性质的证明及应用。

【难点】角的平分线的性质的探究。

三、教学过程

(一)导入新课

1.复习角平分线的画法

2.利用PPT创设情景:

如图是小明制作的风筝,他根据AB=AD,BC=DC.不用度量,就知道AC是∠DAB的角平分线,你知道其中的道理吗?

(二)生成新知

探究做一做(学生独立完成,同组同学交流,找学生到黑板上板演.教师纠正答案)

如图,将∠AOB对折,再折出一个直角三角形(使第一条折痕为斜边),然后展开.观察两次折叠形成的三条折痕,你能得出什么结论?试着证明你的结论.

∴△PDO≌△PEO(AAS)

∴PD=PE.

(三)深化新知

思考:角的平分线的性质在应用时应该注意什么问题?(由学生讨论汇报)

(四)应用新知

1.例题:解决导入中PPT的问题

2.练一练:(1) 下面四个图中,点P都在∠AOB的平分线上,则图形_____ 中PD=PE.

(五)小结作业

小结:通过这节课的学习,你有什么收获?你对今天的学习还有什么疑问吗?

作业:必做题,选做题,思考题:角平分线性质的逆命题并证明。

四、板书设计

五、教学反思

初中英语《Lin Fei’s daily life》教案

Teaching Aims:

Knowledge aim: Students will know Lin Fei’s daily life and some good habits at their home.

Ability aim: Students will improve their listening and speaking skills.

Emotional aim: After this lesson students would like to learn to arrange their life and form good habit in the daily life.

Teaching Key Points:

Students will understand this passage by listening and make a time line of Lin Fei’s life.

Teaching Difficult Points:

How to describe their own life style of the school day?

Teaching Procedures:

Step 1 Warming-up

Do a survey: ask students to fill the questionnaire (with different daily activities and time point, students just need to mark the activities in their time) and invite some students to share.

Step 2 Pre-listening

Show some pictures about Lin Fei’s day and ask students “what does Lin Fei do in a day?

Step 3 While-listening

Play the tape recorder and ask students some question.

Q: What is the distance between his school and home?

Play the tape recorder another time and give students some other questions to practice their listening again.

Q1: When should Lin Fei go to school?

Q2: How long will it take Lin Fei to ride to the bus station?

Listen to the tape for the third time and then students should describe Lin Fei’s daily life in their own words. They will have 3 mins to prepare it.

Step 4 Post-listening

Ask students to look their questionnaires which they filled at the beginning of the class and give them 5 min to make a short story of their daily life, later some students will share the stories in front of the class.

Teacher should give them a guidance of health life style.

Step 5 Summary and homework

Summarize this lesson with students, and then ask them to design a new schedule of their daily life after the class, they will share during next lesson, they also need to read the new passage two times to consolidate the new knowledge.

Blackboard Design:

Teaching Reflection:

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