00:01
Okay, welcome back, numerate.
00:02
We're doing question number, what is it? question number four, chapter six, section one of the calp3 textbook.
00:13
So question number four, consider the vector field in two dimensions, function of x and y, is, in component notation, at ij notation, x, y, notation, x, y, quantity, divided by, by x squared plus y squared.
00:40
So is an x2 plus y squared the magnitude of the vector x i plus y j? so this is a vector pointing in, i'm sorry, it's not x y, x, x, y.
01:04
And the question is, is this vector field rotational or radial? it's neither rotational nor radial to or false.
01:16
Well, what we know here is the magnitude of, y x is square it square it add it squared it so that's a magnitude right so we're divided with the magnet to the vector so this vector is normalized every vector in the vector field is of unit length length one okay but is it a radial field let's see what if i take a point like 1 -1 then at 1 -1 the vector looks delta x is 1 -1 dot the y is 1 okay what about so so it could be radial, i suppose.
02:01
How about 1 negative 1? well, now the vector with 1 negative 1, 1 for x, and negative 1 for y.
02:10
Remember we're switching this.
02:11
So it's negative 1.
02:13
It's negative 1.
02:15
So now it's doing this.
02:19
So that's not radial...