I understand the method of how to express something in the wave form however there is one small stage I'm having difficulties getting right and I don't understand what it is I actually do.
When I have to expand the likes of kcos(x-a), how do I do it? Where does the sin come from? I can do the rest but I keep making mistakes here with the positive and negatives. Can someone just tell me exactly what is being done when this wave form is expanded, what are you actually doing? I think if I can see how to expand it step-by-step will stop making mistakes.
Just so you know what I mean:
When I expand kcos(x-a) how do I know it's not:
1. k(cosxcosa - sinxsina) or
2. k(cosxsina - cosasinx) or
3. k(cosxcosa + sinxsina) or
4. k(cosxsina + cosasinx)
how do I expand it correctly? What am I actually multiplying together! Please help!! Thanks
Wave Function - Can someone please help me out? Watch
- Thread Starter
Last edited by Defensive Gnome; 11-04-2013 at 23:32.
- 11-04-2013 23:24
- 11-04-2013 23:36
It is on the formula sheet so you don't need to memorise them
But for this case it is, k(cosxcosa + sinxsina)Last edited by CSM1996; 11-04-2013 at 23:37.
- 11-04-2013 23:43
You are over-thinking this, it's just the double-angle formulae with a k stuck on the side.