I have two vectors
A = 2i + 3j + 4k
B = 5i + 6j + 7k
I wish to find out the angle between them with the proper sign.
I read (Maths - Inverse Trigonometric Functions - Martin Baker) that the function atan2 is the right way to do it. But I don't find the method to go about it. I want to do it by hand not using some software or excel or something.
Anyone throw some light on it or any other proper method.
Unfortunately, arccos doesn't give the angle "with proper sign".
Some discussions on similar lines (http://www.gamedev.net/community/for...opic_id=503639)
Hello, ontherocks!
Plato's formula is correct.I have two vectors: .
I wish to find out the angle between them.
. .
and it does give the proper sign!
We have: .
Then: .
Therefore: .
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Suppose we have: . . . . the negative of .
The angle between and is given by:
. .
Therefore: .
See?