00:01
All right, so let's say we have three vectors.
00:01
I'm going to do my best to draw them.
00:03
So a is 37, has a length to 37, i mean.
00:08
B has, so let me write this, a is 37.
00:13
B has a length of 63.
00:18
And then we have a third vector c.
00:21
And if this is our horizontal axis, c points down this way.
00:25
C has a length of 24.
00:27
And this angle we'll call theta c is 70 degrees, this angle theta b is 20, and then theta a relative to the positive x axis is 70.
00:40
So a .b, for the first part that we're computing, this is the magnitude of a times the magnitude of b times the cosine of the angle between them, which is theta a minus theta b...