00:01
So the way we want to approach basis problems is first by reducing the number of variables we have and then writing our basis vectors.
00:09
So to reduce the number of variables we have, we want to try to rewrite a variable in terms of the others.
00:15
So in the first case, we have 3x minus 2y plus 5c equals 0.
00:20
If we add 2y to the right hand side and then divide everything by 2, we get 3 .5x plus 2 .1 .2 .2 .2 .2 .5.
00:32
5 halves z is equal to y.
00:40
So now we can write y in terms of x and z.
00:46
In using this equation, we can create our basis vectors.
00:49
So we start making a basis vector where we assume x is 1.
00:55
And we assume z is 0.
00:57
So essentially we assume one variable on the left side is 1 and the rest are 0.
01:02
Well, if x is 1 and z is 0, that means.
01:05
Means y must be three halves.
01:13
Now we do that for our next variable.
01:15
We assume that x is zero and we assume that z is one.
01:20
And if that's the case, then y must be five halves by the equation above.
01:26
And that gives us our basis.
01:28
And we count how many basis factors we have.
01:30
We have two, which means our dimension must be two.
01:36
In part b, we have the equation x minus y equals zero...