I can find the value of $\cos \left(\frac{ \pi}{5}\right)$, but is there a way to prove the equality without finding it?
I tried looking for both algebraic and geometric methods, but couldn't find anything
I can find the value of $\cos \left(\frac{ \pi}{5}\right)$, but is there a way to prove the equality without finding it?
I tried looking for both algebraic and geometric methods, but couldn't find anything