(adsbygoogle = window.adsbygoogle || []).push({}); Trying to follow i "beginer's" proof/derivation from relativity demistified.

I'm trying to follow this proof/derivation in Relativity demystified basically the book is showing transformations and how they work according to the invariance of the speed of light. (im working on chapter 1 pg 9-13 in case any one has the book). The first question i have is, at one point in the book they say that a flash of light moving out from some origin is described by the function of C^2*t^2=x^2+y^2+z^2 (i assume a circle). then they set that equal to zero as well as another coordinate system (F`), and since its in standard form (or something similar) aka only the x direction is moving the y and z and y` and z` cancel out so it leaves us with the equation c^2*t^2-x^2=c^2*t`^2-x`^2 then the author goes on to say "now we use the fact that the transformation is linear while leaving y an z unchanged. the linearity of the transformation means it must have the form x`=Ax+Bc*t

c*t`=Cx+Dc*t

im confused how is it linear aren't there squared terms and how did he rearrange these equations into these two linear equations?

I have more questions but this i all i will ask for now.

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

Dismiss Notice

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!

# Trying to follow i beginer's proof/derivation from relativity demistified.

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