\(\cos^2 θ -\sin^2 θ = \cfrac{1}{2}\) হলে, \(\cos^4 θ – \sin^4 θ\) -এর মান __________
\(\cos^2 θ -\sin^2 θ = \cfrac{1}{2}\) হলে, \(\cos^4 θ – \sin^4 θ\) -এর মান \(\cfrac{1}{2}\)
\(cos^4θ-sin^4θ\)
\(=(cos^2θ+sin^2θ )(cos^2θ-sin^2θ )\)
\(=1×\cfrac{1}{2}\)
\(=\cfrac{1}{2}\)