If α+β=π2 and β+α=α, then tan α equals
(c) α+β=π2=>tan β=cot α tan(β+γ)=tanα=>tan α=tan β+tan γ1−tan β tan γ =>tan α=cot α+tan γ1−cot α tan γ =>tan α−tan γ=cot α+tan γ =>tan α=tan β+2 tan γ