00:03
All right, we have these two vectors, and in part a, the first thing we want us to find is the dot product between the two vectors.
00:10
So we're going to multiply our components, negative 1 times the i component of the other vector square root of 2.
00:18
And we're going to add to that, the j components multiplied together, 1 times the square root of 3, and then plus the k components.
00:28
There's no k component for vector v, so that's 0 times 2.
00:35
Gives us negative square root of 2 plus the square root of 3 and plus 0.
00:42
Don't have to worry about that.
00:43
So there's our dot product.
00:46
The magnitude of the vector comes from the square root of the sum of the component squared.
00:55
So for vector v, it'll be the square root of negative 1 squared plus 1 squared, which gives us the square root of 2.
01:04
And then the magnitude of vector u is going to be the square root of the square root of 2 squared plus the square root of 3 squared plus 2 squared.
01:18
So that gives us 2 plus 3 plus 4, which is the square root of 9, which is 3.
01:26
And now these three answers are going to help us find the answers to the other parts.
01:31
Part b, we want the cosine of theta...