## mkumar441 Group Title please solve this ... suppose A and B are n by n matrices,and AB=I.prove from rank(AB)<=rank(A) that the rank of A is n . So A is invertible and B must be its two-sided inverse. Therefore BA=I(Which is not obvious!). one year ago one year ago

1. mathslover Group Title

So what we have to do .. ?

2. mathslover Group Title

ok sorry wait

3. mathslover Group Title

as given that A is n by n, rank(A) $$\le$$ n and conversely : n = rank($$I_n$$)=rank(AB)$$\le$$rank(A)

4. mathslover Group Title

got my point @mkumar441 ?

5. mkumar441 Group Title

yes i got it thank you for ur quick response

6. mathslover Group Title

Your welcome dear.. also: $\huge{\mathbb{WE}\textbf{LC}\mathcal{OME}\space\textit{TO OPENSTUDY}}$

7. mkumar441 Group Title

i need small favour at wat timings do u present inorder post questions.

8. mathslover Group Title

i didn't get you .. it seems that you are Indian. You can ask in Hindi?

9. mkumar441 Group Title

yes i am indian but i dont Hindi.When do you be in online inorder to clarifiy my doubts?

10. mathslover Group Title

ok i got you now: actually i am present here from 3:00 PM to 9:00 PM (Indian Standard Time_ or there may be breaks but yes: There are gr8 experts present you don't need to care for your clarification of doubts. In case, if your doubt is not answered then you can post the link of your question in the chat. or tag some people having good smart score....

11. mathslover Group Title

lemme introduce you to some experts for your future help: experimentx mukushla Vaidehi09 amistre64 vishweshshrimali5 unklerhaukus and many more

12. mathslover Group Title

just put @ sign before there names and they will be looking on your question as soon as possible.

13. mkumar441 Group Title

Another question ..Suppose A is an m by n matrix of rank r.Its reduced echelon form is R. Describe exactly reduced row echelon form of R transpose (not A transpose).

14. mathslover Group Title

Post that as a new question and tag me there.. I will help you there