Problem 5.234

An observer moves with velocity \(v_{1}=\frac{1}{2} c\) along a straight line. In front of him a source of monochromatic light moves with velocity \(v_{2}=\frac{3}{4} c\) in the same direction and along the same straight line. The proper frequency of light is equal to \(\omega_{0} .\) Find the frequency of light registered by the observer.