Week Three Matrix

Question 1

What is an identity matrix. What happens when you multiply a matrix by the identity matrix

Answer 1

A matrix where the leading diagonal has ones and the rest of the entries are zero. Multiplying a matrix with the identity matrix does not change the matrix.

Question 2

What is an symmetric and anti symmetric matrices

Answer 2

Symmetric matrix = A = A^T
And
Anti Symmetric matrix = A = -A^T

Question 3

What is a determinants?

Answer 3

For 2D it is the factor by which the area changes

And

For 3D it is the factor by which the volume changes

Question 4

How do you know if a matrix is invert able

Answer 4

If the determinant does not equal zero