\(sec^2 θ+tan^2 θ = \cfrac{13}{12}\) হলে, \(sec^4 θ- tan^4 θ\)-এর মান হিসাব করে লিখি।

\(sec^4⁡θ-tan^4⁡θ \)
\(=(sec^2⁡θ )^2-(tan^2⁡θ )^2 \)
\(=(sec^2⁡θ+tan^2⁡θ )(sec^2⁡θ-tan^2⁡θ ) \)
\(=\cfrac{13}{12}×1 [∵sec^2⁡θ-tan^2⁡θ=1] \)
\(=\cfrac{13}{12} \) (Answer)