00:01
Hello, we are given a matrix a and we have that a times 3 2 vector is equal to 6 4 vector in a times the vector 1 1 is equal to 1 1.
00:16
So, if we call this vector 3 2 u and the vector 1 1 v, we have that a u is equal to 2 u, a v equal to v.
00:24
So, u and v are eigenvectors of a with eigenvalue 2 and 1 respectively.
00:31
This is part a.
00:33
Now, let us call the operator phi which is represent whose matrix with respect to the standard basis is a.
00:42
Then, ok this is one net and now let us notice that u and v these are not multiples of each other.
00:51
So, they are linearly independent.
00:53
So, u and v are linearly independent.
00:55
So, u and v let us call that set b, they form a basis of r2.
01:02
Now, the matrix p which let us call this matrix p, let us denote by p the matrix which gives the change of basis matrix from the basis b to basis e which changes coordinates in terms of basis b to coordinates in terms of the basis e.
01:24
Now, this matrix will be 3 2 1 1 and this matrix to change from e coordinates to b coordinates will be the inverse of this matrix.
01:34
Now, the inverse of a 2 by 2 matrix is 1 over the determinant.
01:38
Determinant of this thing is 3 minus 2 1 1 over 1 times we switch or swap the two diagonal entries 2 1 3 and take negative of two this these two entries minus 1 minus 2.
01:54
So, the inverse of p which is this thing is 1 minus 1 minus 2 3.
02:03
Now, ok now the operator phi on u was 2u, operator phi on v was v.
02:14
So, the matrix of the operator phi with respect to the uv basis is 2 is a diagonal matrix and it is to this diagonal matrix.
02:25
Now, the matrix of a is the matrix of the operator with respect to e.
02:30
It is equal to the change of basis is it is equal to the change of basis from e to b...