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I wonder about this Doppler formula.

https://en.wikipedia.org/wiki/Doppler_effect#General

##f=(\frac{c+V_r}{c+V_s})f_0##

The speed of sound is 343m/s

Supposed S (Source) moves to the east, toward R(Receiver) at 70 m/s and R moves to the east at 40 m/s. So the formula is:

##f=(\frac{343-40}{343-70})f_0##

But R will say. No, I'm at rest, it's S who moves toward me at 70-40 = 30 m/s. So the doppler factor would be:

##f=(\frac{343}{343-30})f_0##

No, we can't do that. ##\frac{343-40}{343-70} \neq \frac{343}{343-30}##. Okay...

What about blue/red shifted?

Every where we go, the light will always travel at 300 thousands km/s according to us, right.

What is the formula of doppler ratio, for the frequency that is received by the receiver based on the frequency sent by source?

R is at West

S is at East.

If S moves to west at 0.7c and R moves to west at 0.4c?

A: ##\frac{c-0.4}{c-0.7}## or B ##\frac{c}{c-0.3}## or even C ##\frac{c+0.3}{c}##

If S moves to west at 0.7c and R moves to east at 0.4c?

D: ##\frac{c-0.4}{c-0.7}## or E: ##\frac{c+1.1}{c}## or F ##\frac{c}{c-1.1}##

I suspect F is impossible, but then I have no idea at all.

Unless..., there is aether

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# Doppler for light

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