1 1 12 2 2AH = AB + AC1 1 1 1 1 1⇒ + + = + =2 2 2 2 2 2AB AC HC AH HC...

8)

Ta có:

1 1 1

2

2

2

AH = AB + AC1 1 1 1 1 1⇒ + + = + =

2

2

2

2

2

2

AB AC HC AH HC HF