# Math Help - What's the rank of the matrix?

1. ## What's the rank of the matrix?

I guess the rank of the matrix is 2.But I fail to prove it.Can you help me? Thank you.

2. Originally Posted by tianye
I guess the rank of the matrix is 2.But I fail to prove it.Can you help me? Thank you.

Substract from the k-th row (k-1)-times the SECOND row, and check you always get a multiple of the FIRST row. Since the 1st and 2nd rows are clearly lin. independent you get that the rank indeed is 2.

Tonio

3. ref picture