arsetpopeye
Α + β + γ = 180° γ = 180° - (α + β) cos γ = cos (180° - (α + β)) 1/6 = - cos (α + β) cos (α + β) = -1/6
α - β = 60° ⇒ cos (α - β) = cos 60° = 1/2
cos (α + β) = cos α cos β - sin α sin β = -1/6 cos (α - β) = cos α cos β + sin α sin β = 1/2 ---------------------------------------------------------- - - 2 sin α sin β = -2/3 sin α sin β = 1/3
γ = 180° - (α + β)
cos γ = cos (180° - (α + β))
1/6 = - cos (α + β)
cos (α + β) = -1/6
α - β = 60° ⇒ cos (α - β) = cos 60° = 1/2
cos (α + β) = cos α cos β - sin α sin β = -1/6
cos (α - β) = cos α cos β + sin α sin β = 1/2
---------------------------------------------------------- -
- 2 sin α sin β = -2/3
sin α sin β = 1/3