যদি \(cos^2 θ - sin^2 θ = \cfrac{1}{2}\) হয়, তাহলে \(tan^2 θ\) -এর মান নির্ণয় করো ।
Madhyamik 2018
\(cos^2 θ - sin^2 θ = \cfrac{1}{2}\)
বা, \(cos^2 θ -(1- cos^2 θ) = \cfrac{1}{2}\)
বা, \(cos^2 θ -1+ cos^2 θ = \cfrac{1}{2}\)
বা, \(2cos^2 θ = \cfrac{1}{2}+1=\cfrac{3}{2}\)
বা, \(cos^2 θ =\cfrac{3}{4}\)
বা, \(sec^2 θ =\cfrac{4}{3}\)
বা, \(1+tan^2 θ =\cfrac{4}{3}\)
বা, \(tan^2 θ =\cfrac{4}{3}-1\)
বা, \(tan^2 θ =\cfrac{1}{3}\) (Answer)