# Homework Help: What does this mean?

1. Jun 10, 2010

### stevmg

$$x_2=v*t$$.

I was told that this is incorrect but I don't even know what it is.

The Lorentz equations are:

x' = $$\gamma$$(x - vt)
t' = $$\gamma$$(t - vx/c2)

How would you write that in matrix format?

2. Jun 10, 2010

### Staff: Mentor

I don't either.
Edit: Fill in the question marks.
$$\left[\begin{array}{c} x' \\ t' \end{array}\right] = \left[ \begin{array} {cc} ? & ? \\ ? & ? \end{array} \right] \left[\begin{array}{c} x \\ t \end{array}\right]$$

Last edited: Jun 10, 2010
3. Jun 10, 2010

### Staff: Mentor

$$\left( \begin{array}{cc} x'\\ t' \end{array} \right) = \left( \begin{array}{cc} ? & ?\\? & ?\end{array}\right) \left( \begin{array}{cc} x\\ t \end{array} \right)$$

Fill in the ? marks.

4. Jun 10, 2010

### HallsofIvy

5. Jun 10, 2010

### Staff: Mentor

6. Jun 10, 2010

### Staff: Mentor

I revised my answer, realizing I gave too much help.

7. Jun 10, 2010

### stevmg

I tried I can't make the matrix work.

I am wasting my time...

I'll just read from now on as this array/matrix stuff is pure crap to me.

Thanks anyway

8. Jun 10, 2010

### Staff: Mentor

It might be helpful to write the equations above as
$$x' = \gamma x - \gamma vt$$
$$t' = -\gamma \frac{v}{c^2}x + \gamma t$$

9. Jun 10, 2010

### stevmg

I do not know how to write a matrix in Latex format and no matter how hard I try I never get it.

If I could hand write it, I would but that's not possible here.

I am NOT wasting more time on this and I thank you for your time.

Steve G
Melbourne FL

10. Jun 10, 2010

### Staff: Mentor

You can always just click on one of the ones we provided and copy the code, but no matter.

If the only issue is that you can't write it, that's not a problem. If I write the matrix as:

$$\left( \begin{array}{cc} a & b\\c & d\end{array}\right)$$

We can discuss your answers for the elements a, b, c, and d.

11. Jun 10, 2010

### stevmg

a = $$\gamma$$
b = -$$\gamma$$v
c = -$$\gamma$$v/c2
d = $$\gamma$$

12. Jun 10, 2010

### cronxeh

Thats correct, do you have to solve this linear ODE, or just write it in matrix form?

13. Jun 10, 2010

Perfect.