Forgot password?
 Register account
View 1982|Reply 6

[几何] 一边一中线一平分线相等证全等

[Copy link]

32

Threads

55

Posts

469

Credits

Credits
469

Show all posts

天音 Posted 2016-10-6 22:17 |Read mode
已知$\triangle ABC$和$\triangle A_1B_1C_1$,$AB=A_1B_1$,中线$BD=B_1D_1$,内角平分线$AE=A_1E_1$,求证这两个三角形全等。

0

Threads

4

Posts

20

Credits

Credits
20

Show all posts

rrrrumia Posted 2016-10-21 17:35
中线定理:$c^2+a^2=\frac{1}{2}b^2+2m_b^2$
角平分线长公式:$t_a^2=\frac{bc}{(b+c)^2}[(b+c)^2-a^2]$
若能以$c,t_a,m_b$确定$a,b$,则SSS

32

Threads

55

Posts

469

Credits

Credits
469

Show all posts

 Author| 天音 Posted 2016-10-21 20:24
回复 2# rrrrumia


    怎么证明呢?

0

Threads

4

Posts

20

Credits

Credits
20

Show all posts

rrrrumia Posted 2016-10-22 13:33
回复 3# 天音

证明什么?

32

Threads

55

Posts

469

Credits

Credits
469

Show all posts

 Author| 天音 Posted 2016-10-22 21:57
回复 4# rrrrumia


    你不是说“若能以$c,t_a,m_b$确定$a,b$……”吗?那到底是不是真能确定还要去证明啊

0

Threads

4

Posts

20

Credits

Credits
20

Show all posts

rrrrumia Posted 2016-10-25 07:05
回复 5# 天音

这个.....证不出来
哈哈哈哈哈

32

Threads

55

Posts

469

Credits

Credits
469

Show all posts

 Author| 天音 Posted 2016-12-26 00:21
顶上去,未解决

Mobile version|Discuz Math Forum

2025-5-31 10:57 GMT+8

Powered by Discuz!

× Quick Reply To Top Edit