Combine Equations A and B to give a single equation for v and substitute this in place of v in Equation C.
Rearrange your answer to part (i) to make r the subject of the equation.
z = Δλ/λ0
v = zc
For a planet such as the one orbiting Gliese, the speed v is linked to the mass of the star M and the planet’s orbital radius, by Equation C:
v2 = GM/r
G is Newton’s universal constant of gravitation.
The Attempt at a Solution
(i) v = (Δλ/λ0)c -> (Δλ/λ0)c2 = GM/r
(ii) this is where I'm not sure, is the above correct? I always get roots confused.