Events occuring in 4D spacetime

[member 731016]

Homework Statement

Please see below

Relevant Equations

Please see below

For this problem and solution,

I'm confused by part (c) and (d). I don't understand how the Lorentz formula $ct' = \gamma (ct - \frac{v}{c}x)$ can be used to find the $ct'$ axis. This is because they found the $ct = \frac{v}{c}x$ which is in terms of $x$ not $x'$. Does anybody else please see this subtle bit here?

Thanks!

 

[Orodruin]

Homework Statement: Please see below
Relevant Equations: Please see below

I don't understand how the Lorentz formula ct′=γ(ct−vcx) can be used to find the ct′ axis.

It cannot. It is used to find the x’ axis - which by definition is ct’ = 0.