My question is in the title, here is simple example:
I use formula of abridged multiplication (with help of "factor")
(sin(a+b) - sin(a-b))(sin(a+b) + sin(a-b))
And all I whant now is to use double angle formula like this:
4sin(a)cos(b)cos(a)sin(b) = sin(2a)sin(2b)
and keep on working with my double angles! Is it possible? because after few hours of searching I'm not sure.
I'm a beginner, and I have a lot of stupid questions and no one to answer it.
So i hope for you're help:)