Homework Help: Is this a subspace of R^4

1. Mar 25, 2012

saintdick

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

Is this a subspace of R^4, (2x+3y, x, 0 , 1) . Give reasons

2. Relevant equations

3. The attempt at a solution

I am completely stuck at this one

2. Mar 25, 2012

kru_

A subset U of V is a subspace of V if it satisfies the properties needed to be a vector space: additive identity; closure under vector addition; closure under scalar multiplication.

Check that your given subset satisfies the properties.

a) Is there an additive identity from your set for R^4?

b) If you take two vectors from your given space, a and b, is a+b still in your set?

c) Is the scalar multiple of any vector in your set still in the set?

Last edited: Mar 26, 2012
3. Mar 26, 2012

HallsofIvy

You might want to look particularly at the fourth component in a scalar product such as 2v.