pt BC:x+y-3=0.goi H la chan duong cao.vi H thuoc BC nen H(x;3-x).vectoAH*vectoBH=0=>H(1;2) hayH(-1/2;7/2).goi AK la daon thang chia tam giac ABC thanh 2 tam giac thoa man de bai .vi K thuoc BC nen K(x;3-x)BK=cb2(2)*(x-1) =>dien tich cua tam giac chua dinh B la:Sb=1/2*AH*cb2(2)*(x-3)tuong tu Sc=1/2*AH*cb2(2)*(x-3)Ma Sb=3Sc =.x=8K(8;-5).ban tu viet pt AK nhe
pt BC:x+y-3=0.goi H la chan duong cao.vi H thuoc BC nen H(x;3-x).vectoAH*vectoBH=0=>H(1;2) hayH(-1/2;7/2).goi AK la daon thang chia tam giac ABC thanh 2 tam giac thoa man de bai .vi K thuoc BC nen K(x;3-x)BK=cb2(2)*(x-1) =>dien tich cua tam giac chua dinh B la:Sb=1/2*AH*cb2(2)*(x-3)tuong tu Sc=1/2*AH*cb2(2)*(x-3)Ma Sb=3Sc =.x=8K(8;-5).=>vectoAK=(11;-6)=>pt AK=6x+11y+7=0