在△ABC中,若tanAtanC+tanBtanC=tanAtanB,且a2+b2=mc2,则实数m等于_.
问题描述:
在△ABC中,若tanAtanC+tanBtanC=tanAtanB,且a2+b2=mc2,则实数m等于______.
答
已知等式即 sinAsinCcosAcosC+sinBsinCcosBcosC=sinAsinBcosAcosB,sinAsinCcosB+cosAsinBsinCcosAcosBcosC=sinAsinBcosAcosB即sinC(sinAcosB+cosAsinB)cosAcosBcosC=sinAsinBcosAcosB可得sinAsinBsinC=si...