\(\int {\frac{{{\rm{sin}}\,{\rm{x + cos}}\,{\rm{x}}}}{{\sqrt {{\rm{sin}}\,{\rm{2x}}} }}} \) dx = sin^-1 (sin x - λ cos x) + C, \(\left( {\frac{{\rm{\pi }}}{{\rm{4}}}\, < \,{\rm{x}}\,{\rm{ < }}\,\frac{{\rm{\pi }}}{2}} \right)\) then λ equals