sec2θ + tan2θ = 7/12 হলে, sec4θ - tan4θ = ?

প্রশ্ন: sec2θ + tan2θ = 7/12 হলে, sec4θ - tan4θ = ?সমাধান:sec4θ - tan4θ= (sec2θ - tan2θ)(sec2θ + tan2θ)= 1 × (sec2θ + tan2θ) [যেহেতু, 1 + tan2θ = sec2θ]= 1 × (7/12)= 7/12