- #1
pyroknife
- 613
- 4
Let A be an invertible matrix. Show that if λ is
an eigenvalue of A, then 1/λ is an eigenvalue of
A^−1.det((A-λI))
det((A-λI)^-1)
=det(A^-1 - λ^-1 * I)
=det(A-1-1/λ*I)
Is this enough to show that?
Another question I have is:
Let A be an n × n matrix. Show that A is not
invertible if and only if λ = 0 is an eigenvalue
of A.
Not sure how to approach this prob.
det(A-λI)=0
det(A-0I)=0
det(A)=0
But idk how to show what the problem is asking.
an eigenvalue of A, then 1/λ is an eigenvalue of
A^−1.det((A-λI))
det((A-λI)^-1)
=det(A^-1 - λ^-1 * I)
=det(A-1-1/λ*I)
Is this enough to show that?
Another question I have is:
Let A be an n × n matrix. Show that A is not
invertible if and only if λ = 0 is an eigenvalue
of A.
Not sure how to approach this prob.
det(A-λI)=0
det(A-0I)=0
det(A)=0
But idk how to show what the problem is asking.