Cho tam giác ABC, AC> AB, trung tuyến AM, đường cao AH. \(AB^2\)= \(AM^2\)-\(2BM.MH\) +\(MB^2\). \(AC^2\)= \(AM^2\)+ \(MC^2\)+2CM.MH. CMR: a/\(AB^2\)+ \(AC^2\)= \(\frac{BC^2}{2}\)+ \(2AM^2\)B/ \(AC^2\)-\(AB^2\)=...
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Cho tam giác ABC, AC> AB, trung tuyến AM, đường cao AH. \(AB^2\)= \(AM^2\)-\(2BM.MH\) +\(MB^2\). \(AC^2\)= \(AM^2\)+ \(MC^2\)+2CM.MH. CMR:
a/\(AB^2\)+ \(AC^2\)= \(\frac{BC^2}{2}\)+ \(2AM^2\)
B/ \(AC^2\)-\(AB^2\)= 2BC.MH
