# Homework Help: Vector subspace question

1. Oct 4, 2004

### phy

Hi guys. I need some help with question #5 from my assignment. If someone can just tell me how to get the question started, it would be great. Thanks

http://img34.exs.cx/img34/8320/algebra1.jpg

2. Oct 4, 2004

### vsage

If A, B and C generate U then e*A +f*B + g*C generates every element in U (in this case that a b c d matrix). Of course you know this already seeing as you did the rest of those. What does VecR(A, B, C) mean? No linear alg. book I've ever worked with uses that notation.

3. Oct 4, 2004

### phy

I'm not 100% sure on this either but somebody who I spoke to said that VecR(A, B, C) is just a spanning set. I couldn't find it in my textbook either.

So would I just set e*A +f*B + g*C equal to the matrix with entries a b c d and then solve?

4. Oct 4, 2004

### vsage

Ok that's what I figured. Yeah and you should get some sort of proportionality between the four and not a numerical answer once you solve it out.

5. Oct 4, 2004

### phy

Alrightie I'll do that. Thanks a lot =)