# Homework Help: New to Linear Algebra

1. Aug 23, 2009

### zacman2400

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

suppose x=x0+tv and y=y0+sw are two parametric representations of the same line l in r^n
a. show that there are scalars t0 and s0 such that y0=x0+t0v and x0=y0+s0w
b. show that v and w are parallel

3. The attempt at a solution

a. same line thus
y0+sw=x0+tv
when s0w=t0w then y0=x0 (essentially the solution...I think)

b. not sure at all
I don't like saying because the problem states: parametric rep of same line then must be parallel, but this is the most obvious statement to me

2. Aug 23, 2009

### Tom Mattson

Staff Emeritus
For part b pick any two points on the line $x_1$ and $x_2$ corresponding to $t_1$ and $t_2$, respectively. Since the second parameterization is of the same line then there must exist $s_1$ and $s_2$ such that $y_1=x_1$ and $y_2=x_2$, respectively. Can you take it from there?

3. Aug 23, 2009

### zacman2400

leading us to the idea that y1-x1=y2-x2 meaning 0=0, thus parallel

4. Aug 23, 2009

### Tom Mattson

Staff Emeritus
No, you need to slow down and be more careful. You're trying to show that w is parallel to v, which means that w is a nonzero scalar multiple of v.