D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DED是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE (2)当A
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![D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DED是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE (2)当A](/uploads/image/z/7002541-37-1.jpg?t=D%E6%98%AFBC%E4%B8%AD%E7%82%B9%2CAM%E6%98%AF%E2%96%B3ABC%E7%9A%84%E5%B9%B3%E5%88%86%E7%BA%BF%2CCE%E2%8A%A5AM%E4%BA%8EE%2C%E8%BF%9E%E6%8E%A5DE%EF%BC%881%EF%BC%89%E5%BD%93AB%EF%BC%9CAC%E6%97%B6%2CAM%E4%B8%BA%E2%96%B3ABC%E5%86%85%E8%A7%92%E5%B9%B3%E5%88%86%E7%BA%BF%2C%E8%AF%81%EF%BC%9AAC-AB%3D2DED%E6%98%AFBC%E4%B8%AD%E7%82%B9%2CAM%E6%98%AF%E2%96%B3ABC%E7%9A%84%E5%B9%B3%E5%88%86%E7%BA%BF%2CCE%E2%8A%A5AM%E4%BA%8EE%2C%E8%BF%9E%E6%8E%A5DE%EF%BC%881%EF%BC%89%E5%BD%93AB%EF%BC%9CAC%E6%97%B6%2CAM%E4%B8%BA%E2%96%B3ABC%E5%86%85%E8%A7%92%E5%B9%B3%E5%88%86%E7%BA%BF%2C%E8%AF%81%EF%BC%9AAC-AB%3D2DE+%EF%BC%882%29%E5%BD%93A)
D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DED是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE (2)当A
D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE
D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE
(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE
(2)当AB>AC时,AM为△ABC外角平分线,正上述三边关系
D是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DED是BC中点,AM是△ABC的平分线,CE⊥AM于E,连接DE(1)当AB<AC时,AM为△ABC内角平分线,证:AC-AB=2DE (2)当A
(1)延长AB,CE,使AB与CE交于点F
因为AM为△ABC内角平分线,且CE⊥AM于E,则△AFC为等腰三角形,即AC=AF,CE=EF
所以AC-AB=AF-AB=BF
又因为D是BC中点,且CE=EF,则DE//BF,
所以DE:BF=CD:CB=1:2,则BF=2DE,即AC-AB=2DE
(2)延长AB,CE,使AB与CE交于点F
因为AM为△ABC外角平分线,且CE⊥AM于E,则△AFC为等腰三角形,即AC=AF,CE=EF
所以BF=AF+AB=AC+AB
又因为D是BC中点,且CE=EF,则DE//BF,
所以DE:BF=CD:CB=1:2,则BF=2DE,即AC+AB=2DE