# Equality

• Mar 31st 2007, 10:40 PM
mike1
Equality
What do I need to do to solve what the value of k does equality hold:

|1 0 4| |1 0 4|
|3 0 9|=k |3 0 9|?
|5 5 20| |5 5 20|
• Mar 31st 2007, 10:48 PM
Jhevon
Quote:

Originally Posted by mike1
What do I need to do to solve what the value of k does equality hold:

|1 0 4| |1 0 4|
|3 0 9|=k |3 0 9|?
|5 5 20| |5 5 20|

are you trying to write matrices?

notice that the matrix (or determinant of a matrix, not sure which you are doing) on the left is the same as on the right, except for the k. so we must have k=1, otherwise the equality wouldn't hold
• Apr 1st 2007, 03:08 AM
mike1
I am trying to do a matrices. I think my answer would be 1, but I am confused about the question too.
• Apr 1st 2007, 06:50 AM
ThePerfectHacker
Quote:

Originally Posted by mike1
I am trying to do a matrices. I think my answer would be 1, but I am confused about the question too.

The answer is k=1 because both matrices are unchanged.
• Apr 1st 2007, 06:50 AM
Jhevon
Quote:

Originally Posted by mike1
I am trying to do a matrices. I think my answer would be 1, but I am confused about the question too.

well, one way to look at it is that the k is a scalar multiple, so you can multiply each element within the matrix by k, then to have equality, you would equate corresponding components.

so 1 = 1k
0 = 0k
4 = 4k
.
.
.
and so on

then the obvious answer for k is 1