In order to see optical beats with the naked eye, the light would have to have a really close frequency In this question you will need to use the

In order to see optical beats with the naked eye, the light would have to have a really close frequency

In this question you will need to use the approximation that (1+x)^−1≈(1−x)

if x is much smaller than 1.

For the yellow light of wavelength 589.0nm