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nguyenbahiep1

[laTEX]BC \cap ox \Rightarrow B (1,0) \\ \\ x_A = a \Rightarrow A(a,0) \\ \\ x_C = a \Rightarrow y_C = \sqrt{3}a-\sqrt{3} \\ \\ C(a, \sqrt{3}a-\sqrt{3}) \\ \\ G (\frac{2a+1}{3}, \frac{\sqrt{3}(a-1)}{3}) \\ \\ AB = |a-1|, AC = \sqrt{3}|a-1| , BC = 2|a-1| \\ \\ S_{ABC} = \frac{\sqrt{3}}{2}(a-1)^2 \\ \\ r = \frac{2S}{AB+BC+AC} = 2 \\ \\ |a-1| = 2\sqrt{3}+2 \\ \\ TH_1: a = 2\sqrt{3}+3 \Rightarrow G (\frac{7+4\sqrt{3}}{3},\frac{6+2\sqrt{3}}{3}) \\ \\ TH_2: a = -2\sqrt{3}-1 \Rightarrow G (\frac{-1-4\sqrt{3}}{3},\frac{-6-2\sqrt{3}}{3})[/laTEX]
 
S

sevenlegend

nguyenbahiep1 said:
[laTEX]BC \cap ox \Rightarrow B (1,0) \\ \\ x_A = a \Rightarrow A(a,0) \\ \\ x_C = a \Rightarrow y_C = \sqrt{3}a-\sqrt{3} \\ \\ C(a, \sqrt{3}a-\sqrt{3}) \\ \\ G (\frac{2a+1}{3}, \frac{\sqrt{3}(a-1)}{3}) \\ \\ AB = |a-1|, AC = \sqrt{3}|a-1| , BC = 2|a-1| \\ \\ S_{ABC} = \frac{\sqrt{3}}{2}(a-1)^2 \\ \\ r = \frac{2S}{AB+BC+AC} = 2 \\ \\ |a-1| = 2\sqrt{3}+2 \\ \\ TH_1: a = 2\sqrt{3}+3 \Rightarrow G (\frac{7+4\sqrt{3}}{3},\frac{6+2\sqrt{3}}{3}) \\ \\ TH_2: a = -2\sqrt{3}-1 \Rightarrow G (\frac{-1-4\sqrt{3}}{3},\frac{-6-2\sqrt{3}}{3})[/laTEX]
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cho em hỏi trọng tâm thứ 2 ở đâu vậy anh****************************?????
 
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