De la 2surse coerente aflate la distanta d=2 metri una de alta se propaga intrun mediu elastic unde cu viteza =340 m/s. la distanta L =4 metri de la mijlocul dintre surse perpendicular pe segmentul care le uneste a fost inregistrat un maxim de interferenta iar urmatorul la distanta de 1, 5 metri de la acesta pe linia paralela cu cea pe care se afla sursele. Care este frecventa de oscilatie a surselor?

Explanation:

The text is in Romanian language, however here's a clearer rendering which reads;

"From 2 coherent sources at a distance d = 2 meters from each other, it propagates in an elastic medium where with velocity = 340 m/s. At a distance L = 4 meters from the middle between sources perpendicular to the segment joining them a maximum of interference and the next at a distance of 1.5 meters from it on the line parallel to the one on which the sources are located. What is the frequency of oscillation of the sources?."

what is the actual question though?