A heavenly body is receding from earth such that the fractional change in `lambda` is 1, then its velocity is

The radial speed of a galaxy is 1.2 xx 10^(6)m//s receding away from earth. What is the percentage change in wavelength in the observed spectrum ?

Why do the heavenly bodies seem to move from east to west?

Why do the heavenly bodies seem to move from east to west?