Use the arccosine function.
.
I can do the full equation but the problem is trying to find the angle between two vectors,
So if I had the problem
Find angle between these two given vectors:
A = (2,1,-3)
B = (1,-1,1)
A.B = -2
|a| = sqrt14
|b| = sqrt3
so
-2/sqrt42 = -0.309
I know cos(thetre) = A . B / a b
but I'm still not sure how to go about finding the angle
how do I work out the angle?? Iam quite new to vectors so Iam guessing this is quite obvious,
Please can someone point it out for me!!
I have the answer 108 degrees in my notes I just dont know how to get that!!