clementine
New member
- Joined
- Jun 21, 2006
- Messages
- 8
sin3xsinx=1/2(cos2x-cos4x)
someone please help!! PLEASE!!!
someone please help!! PLEASE!!!
On the right side: \(\displaystyle \,\cos(2x)\:=\:\cos(3x\,-\,x)\:=\:\cos(3x)\cos(x)\,+\,\sin(3x)\sin(x)\)\(\displaystyle \sin(3x)\sin(x)\:=\:\frac{1}{2}\left[\cos(2x)\,-\,\cos(4x)\right]\)