In certain physics textbooks, one starts with the assumption (in a one linear and one time dimension) that(adsbygoogle = window.adsbygoogle || []).push({});

1) x^{2}- c^{2}t^{2}= x'^{2}- c^{2}t'^{2}

I don't want to go into that. Let us start from there.

Now, if you assume that

2) x = vt, then

3) x' = 0 always because the origin is moving at v along the x-axis so that x' is always zero.

Using those three bits of information one can derive the Lorentz equations:

x' = [tex]\gamma[/tex](x - vt)

t' = [tex]\gamma[/tex](t - xv/c^{2})

where [tex]\gamma[/tex] = SQRT[1 - v^{2}/c^{2}] (I can't get the square root to come out in LATEX)

I have tried, tried, tried to do that but I cannot.

Anyone can help?

If I substitute the Lorentz equations back into the above three bits of information, it will work out but that's backwards. I want to do it forwards.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Derivation of an old-time formula

**Physics Forums | Science Articles, Homework Help, Discussion**