三角形abc,(a^2+b^2-c^2)/(a+b-c)=c^2,acosB=bcosA,判断三角形的形状

acosB=bcosA
=> sinA/sinB = cosA/cosB
=>sinA*cosB - cosA*sinB = 0
=>SIN(A-B)=0
=> A=B
=a=b
(a^2+b^2-c^2)/(a+b-c)=c^2 这个条件有问题啊 ,单独判断量纲就不对