Cho tam giác ABC cân tại A .Trên tia đối của các tia BC và CB .Lấy theo thứ tự 2 điểm D và E sao cho BD=CE
A) CM:tam giác ADE cân
B)Gọi M là trung điểm của BC .CM:AM là phân giác góc DAE
C)Từ B và C kẻ BH và CK theo thứ tự vuông góc với AD và AE .CM:BH=CK
BÀI NÀY TỚ KO BIẾT LÀM GIÚP TỚ VỚI NHÉ????????
a) Ta có: \(\widehat{ABD}+\widehat{ABC}=180^0\)(hai góc kề bù)
\(\widehat{ACE}+\widehat{ACB}=180^0\)(hai góc kề bù)
mà \(\widehat{ABC}=\widehat{ACB}\)(Hai góc ở đáy của ΔBAC cân tại A)
nên \(\widehat{ABD}=\widehat{ACE}\)
Xét ΔABD và ΔACE có
AB=AC(ΔABC cân tại A)
\(\widehat{ABD}=\widehat{ACE}\)(cmt)
BD=CE(gt)
Do đó: ΔABD=ΔACE(c-g-c)
Suy ra: AD=AE(Hai cạnh tương ứng)
Xét ΔADE có AD=AE(cmt)
nên ΔADE cân tại A(Định nghĩa tam giác cân)
vì ∠ACB +∠ACE=180o(2 góc kề bù)![](data:image/png;base64,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)
=>∠ACE=180o-∠ACB
mà ∠ABC=∠ACB(ΔABC cân tại A)
=>∠ACE=∠ABD=180o-∠ACB
Xét ΔABD và ΔACE có:
AB=AC(ΔABC cân tại A)
BD=CE(giả thuyết)
∠ABD=∠ACE(chứng minh trên)
=>ΔACE=ΔABD(C-G-C)
=>ΔADE cân tại A
vì M là trung điểm của BC nên MC=MB
mà BD=CE(giả thuyết)
=>ME=MD
xét ΔAME và ΔAMD có:
AM là cạnh chung
AE=AD(câu a)
ME=MD(chứng minh trên)
=>ΔAMD=ΔAME(C-C-C)
=> ∠DAM=∠EAM(2 góc tưng ứng)
=>AM là tia phân giác của ∠DAE
ta có:∠CAE=∠BAD(câu a)
=>∠BAH=∠CAK=∠BAC+∠CAH
xét 2 tam giác vuông AHB và AKC có:
AB=AC(Δ ABC cân tại A)
∠CAK=∠BAH(chứng minh trên)
=>ΔBAH=ΔCAK(cạnh-huyền-góc-nhọn)
=>BH=CK(2 cạnh tưng ứng)