Answer:
Please see attached picture for full solution.
I changed the rhs to tanθ/tanθ+1 since the angle cannot be A and θ.
tanθ= sinθ/cosθ
cosθ/sinθ= cotθ= 1/tanθ
From 4th last line, here is the step I skipped:
1 ÷ [1 +(1/tanθ)] = 1 ÷ [(tanθ/tanθ)+(1/tanθ)]