68. Two speakers spaced d = 0,5 m apart and reproduce the same musical tone at a frequency ν = 1500 Hz. The receiver is located at a distance l = 4 m from the center speaker. Taking the sound velocity υ = 340 m / s, determine at what distance from the center line parallel to the dynamics necessary to push the receiver, so he gave the first interference minimum.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)