用几何法证明:根号下(x1^2+y1^2)+根号下(x2^2+y2^2)大于等于根号下(x1-x2)^2+(y1-y2)^2

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用几何法证明:根号下(x1^2+y1^2)+根号下(x2^2+y2^2)大于等于根号下(x1-x2)^2+(y1-y2)^2

证明:在直角坐标系中取点A(x1,y1),B(x2,y2),原点为O(0,0)则|AO|=√(x1^2+y1^2)|BO|=√(x2^2+y2^2)|AB|=√[(x1-x2)^2+(y1-y2)^2]在△ABO中,两边之和大于第三边|AO|+|BO|>|AB|即√(x1^2+y1^2)+√(x2^2+y2^2)>√[(x1-x...