- #1

- 7

- 0

i can't find about how id prove it

i know A^2=A and A^-1 exists

so too AB=BA

its obvious to say elements must be 1 or 0 but finding an overal rule isnt obvious to me

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter keelejody
- Start date

- #1

- 7

- 0

i can't find about how id prove it

i know A^2=A and A^-1 exists

so too AB=BA

its obvious to say elements must be 1 or 0 but finding an overal rule isnt obvious to me

- #2

HallsofIvy

Science Advisor

Homework Helper

- 41,847

- 966

If A has an inverse, multiply both sides of A^{2}= A by A^{-1}!

- #3

- 525

- 16

The proof above (HallsofIvy) is much more elegant, and applicable for all nxn matrices, but setting up the arbitrary matrix would probably be a good way to practice your matrix math.

Share: