A visual proof…

Settembre 8, 2021·Biagio

so, we can convince ourselves that:

$\cos \left( {2x} \right) = {\cos ^2}\left( x \right) - {\sin ^2}\left( x \right)$

$\sin \left( {2x} \right) = 2\sin \left( x \right)\cos \left( x \right)$

Tema Diary di B. Raucci