Find an exact expression for $ \cos 42^{\circ} $ . The following information will be useful:
$ \cos \left(18^{\circ}\right)=\sqrt{\frac{\sqrt{5}+5}{8}} $ and $ \sin \left(18^{\circ}\right)=\frac{\sqrt{5}-1}{4} $

Question

Find an exact expression for  $ \cos 42^{\circ} $  . The following information will be useful:
$ \cos \left(18^{\circ}\right)=\sqrt{\frac{\sqrt{5}+5}{8}} $ and $ \sin \left(18^{\circ}\right)=\frac{\sqrt{5}-1}{4} $

Quizplus · Accepted Answer

The Answer of Find an exact expression for  $ \cos 42^{\circ} $  . The following information will be useful:
$ \cos \left(18^{\circ}\right)=\sqrt{\frac{\sqrt{5}+5}{8}} $ and $ \sin \left(18^{\circ}\right)=\frac{\sqrt{5}-1}{4} $

Find an Exact Expression For cos⁡42∘ \cos 42^{\circ} cos42∘ the Following Information Will Be Useful

Find an Exact Expression For $\cos 42^{\circ}$ the Following Information Will Be Useful