In ΔABC cosAcosBcosC=3-18 and sinAsinBsinC=3+38, then the value of tanA+tanB+tanC=
3+33−1
3+43−1
6−33−1
3+23−1
We have
sinAsinBsinCcosAcosBcosC=3+33-1⇒tanAtanBtanC=3+33-1 ⇒tanA+tanB+tanC=3+33-1 ∵A+B+C=π⇒tanA+tanB+tanC=tanAtanBtanC