TAP702-3 Doppler derivation for light

[michel123456]

From this http://tap.iop.org/astronomy/astrophysics/702/file_47550.doc page 8 here below:(red rectangle mine)

 

 

In the rectangle something that made me rise my eyebrows: the waves have covered a distance of v+c

???

Explained after that (Speed = distance/time and time = 1 second) so v+c happened in one sec, thus O.K. in one second v+c represents a distance and not a speed.

O.K. but still...

 

The waves have covered a distance of v+c in 1 sec ???

 

Although we are apparently observing the photons coming at us a velocity c, doesn't that mean that the waves have travelled at speed faster than c?