от Anubis » 10 Апр 2011, 17:32
[tex]AH=x[/tex]
[tex]\triangle AHC \sim \triangle ACB \Rightarrow \frac{AH}{AC} = \frac{HC}{CB} = \frac{AC}{AB} \Leftrightarrow \fbox {\frac{x}{AC}} = \frac{4}{CB} = \fbox {\frac{AC}{10}} \Rightarrow AC = \sqrt{10 x}[/tex]
[tex]AH^2 + CH^2 = AC^2 \Leftrightarrow x^2 + 16 = 10 x \Leftrightarrow x^2 - 10 x + 16 = 0 \Leftrightarrow x_{1} = 8, \, x_{2} = 2[/tex]
[tex]\fbox {1.} \, x = 8: \, AH = 8, \, AC = 4\sqrt{5}, \, BC = 2\sqrt{5}[/tex]
[tex]\fbox {2.} \, x = 2: \, AH = 2, \, AC = 2\sqrt{5}, \, BC = 4\sqrt{5}[/tex]