Question

Will give medal. I need help solving for A where 0 11 years ago

Answer 1

\[\sin x+\cos x=\sqrt{2}\left( \sin x~\frac{ 1 }{ \sqrt{2} }+\frac{ 1 }{ \sqrt{2}} \cos x~\right)\]
\[\cos \frac{ \pi }{ 4 } =\sin \frac{ \pi }{ 4 } =\frac{ 1 }{ \sqrt{2} }\]
complete it.