Wave interference from 2 point source

[Kinto]

Hi,

I am trying to understand wave interference from 2 point source. The derived formula in the textbook says |p1s1 - p1s2| = 1/2 wavelength. How did they derive at the 1/2 wavelength? I connected P1 to source 1 (s1) and then to source 2 (s2). But I don't understand how they've arrived at half wavelength.

Thanks

[himanshu121]

There are many possiblities Pls Show a diag how relatively the two point sources are related

And obviously the difference is path difference which depends upon many factors what is initial phase difference, how they are positioned w.r.t P etc...

Is it a complete information Is sources Placed in as in Youngs double slit Experiment etc[?] [?] [?]