00:01
We wanna show the two successive lorentz transformations in the same direction, give us the velocity addition law.
00:11
So let's, so x zero is gonna be my initial, the x zero, t zero is my initial frame.
00:21
And so after the first transformation, it puts it in the x one, t one frame that has velocity v one, and then the velocity t two puts us in the x two, t two frame, okay? there should be a one there.
00:49
So x two, i can substitute in the x one and t one.
00:56
I'm only gonna look at x and not worry about t, because in fact, it'll give me everything i need.
01:03
All i have to really do is calculate the gamma factor for the combined transformation, and that will tell me what the velocity is, which is all i really wanna find, okay? so the gamma factor for the combined transformation is the coefficient that multiplies x zero, okay? and then the velocity of the combined frame, we can get from the gamma factor, looks like that.
02:08
And i'm squaring it, so i don't have to carry the square roots around.
02:21
And then i'm going to substitute in for gammas.
02:27
Remember, that'll put the one minus v over c squared stuff in the numerator like that.
02:50
And then let's expand all that, put it, i got this one here, i gotta bring that in, get it all over the same denominator, then expand that square, multiply all that stuff out...