在△ABC中,求证：（a2-b2）/c2 = (sin A – sin B)/sin C

由正弦定理有：a=2RsinA,b=2RsinB,c=2RsinC所以：(a^2-b^2)/c^2=((sinA)^2-(sinB)^2)/(sinC)^2=(sinA-sinB)(sinA+sinB)/(sinC)^2你的题目抄错了,因为sinC=sin(A+B)=sinAcosB+sinBcosA≤sinA+sinB（仅当A=B=0取等号）...