If A+B+C=π, then ∣∣ ∣ ∣∣sin(A+B+C)sinBcosC−sinB0tanAcos(A+B)−tnaA0∣∣ ∣ ∣∣ is equal to
If A + B + C = π and cos A = cos B cos C, then tan B tan C is equal to