题目内容：

△ABC中,已知sinB(tanA+tanC)=tanAtanC求证a,b,c成等比

优质解答

证明：已知sinB(tanA+tanC)=tanAtanC,那么：sinB(sinA/cosA + sinC/cosC)=(sinAsinC)/(cosAcosC)即sinB(sinAcosC+cosAsinC)/(cosAcosC)=(sinAsinC)/(cosAcosC)所以：sinBsin(A+C)=sinAsinC又sin(A+C)=sin(180°-B)=s...