|
|
![[parent]](http://images.planetmath.org:8080/images/uparrow.png) Viewing Message
|
|
|
| ``double angle identity''
by perucho on 2004-05-17 11:28:37 |
|
| Also through Euler formula (equivalent to Moivre formula mentioned by Mr. Akrowne):
e^{2i\alpha}=cos{2\alpha}+isin{2\alpha} (1)
(e^{i\alpha})^2=(cos{\alpha}+isin{\alpha})^2=
=(cos{\alpha}^2-sin{\alpha}^2)+i(2sin{\alpha}cos{\alpha}) (2)
and equating.
|
| | [ reply | up ] |
|
|
|
|
|
|
