IfAngle θ is divided into two parts such that the tangents of the one part is λ times the tangent of other, And ϕ is their difference, then show that .
Let α And β be the two parts of angle θ.
Then, given θ = α + β And ϕ = α - β
Consider tan α = λ tan β
Applying componendo And dividendo,
We know that sin(A ±B) = sinA cosB ± cosA sinB