Chapter 36, Problem 31AP

Two coherent waves, coming from sources at different locations, move along the x axis. Their wave functions are

$E_1=860\sin \left[\frac{2\pi x_1}{650}-924\pi t+\frac{\pi }{6}\right]$

and

$E_2=860\sin \left[\frac{2\pi x_2}{650}-924\pi t+\frac{\pi }{8}\right]$

where E₁ and E₂ are in volts per meter, x₁ and x₂ are in nanometers, and t is in picoseconds. When the two waves are superposed, determine the relationship between x₁, and x₂ that produces constructive interference.