a、b、c的公式（abc不等于0）k=c/(a-b)=a/(b-c)=b/(c-a)问k的值是多少?
问题描述：
a、b、c的公式（abc不等于0）k=c/(a-b)=a/(b-c)=b/(c-a)问k的值是多少?
答
若m1/n1=m2/n2,则(m1+m2)/(n1+n2)=m1/n1；k=(a+c)/(a-c)=(a+b)/(b-a),可得c=[(k-1)/(k+1)]a,b=[(k+1)/(k-1)]a,代入a/(b-c)=k中化简得(k^2-1)/(4k)=k,即k^2=-1/3.如果在实数域下无值，复数域下k=(√3/3)i，i为虚单位
答
k=c/(a-b)=a/(b-c)=b/(c-a)分解为
c/(a-b)=a/(b-c)
a/(b-c)=b/(c-a)
c/(a-b)=b/(c-a)
求得abc后得k
答
等于0
由k=c/(a-b)=a/(b-c)=b/(c-a）得出
a^2=bc
b^2=ac
c^2=ab
k^2=c^2/(a^2+b^2-2ab)=……=c/a+c/b-2=0