# Matrix Transformations

1. Oct 20, 2011

### Gurvir

1. The problem statement, all variables and given/known data

2. Relevant equations
None

3. The attempt at a solution

Well guys, this is a problem I've been having for the last 2 days and with my midterm tomorrow I have no time to fiddle around with it.

So, I do not understand how (where it says b) how

Im going to use a division symbol ( / ) for indicating a break in the line.

(3x+5y)[1 / -2] + (4x+7y)[-1 / 1] is equal to [-x-2y / -2x-3y]

I have no understanding of this, because if you think of [x / y] which means it should be [(3(1) + 5(-2)) / (4(-1) + 7(1))]

which is equal to [3x-10y / -4x+7y] which is not equal what the answer is.

I hope you understand what I am asking and need a response asap, thanks in advance!

2. Oct 20, 2011

### Staff: Mentor

No. It means that (3x + 5y) is a scalar that multiplies each component of the vector <1, -2>T. Here T means transpose. I'm writing a column vector as a row vector. So you get the vector <3x + 5y, -6x - 10y>T

Same with (4x + 7y). It multiplies each component of <-1, 1>T.

Now add the two vectors together and you should get <-x - 2y, -2x - 3y>T.

3. Oct 20, 2011

### Gurvir

AHHH! Hahaha, I'm stressing to much! Thank you so much! Finally, finished Matrix Transformations. Well studying it :D