在△ABC中,若tanAtanC+tanBtanC=tanAtanB,且a2+b2=mc2,则实数m等于______.
人气:304 ℃ 时间:2019-11-09 05:25:45
解答
已知等式即 sinAsinCcosAcosC+sinBsinCcosBcosC=sinAsinBcosAcosB,sinAsinCcosB+cosAsinBsinCcosAcosBcosC=sinAsinBcosAcosB即sinC(sinAcosB+cosAsinB)cosAcosBcosC=sinAsinBcosAcosB可得sinAsinBsinC=si...
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