Physics
posted by Needs Physics help desperately .
Someone has already posted this question, but their's was never answered, so hopefully someone can answer this. Thanks. An interference pattern is set up by two point sources of the same frequency, vibrating in phase with one another. A point on the second nodal line is 50.0 cm from one source and 59 cm from the other. The speed of the waves is 35 cm/s. Calculate the frequency of the sources. I know you do path difference (like PmsPms) and then do the universal wave equation.

Look for the answer I posted to the original question.

If there is a node (minimum) then the path difference is a multiple of odd 1/2 Lambda.
(n+ 1/2 )lambda= .09 meters
Now the first nodal line will be n=0, the second at n=1. Check my thinking
Now you have lambda, and the wave equation will give frequency.
freq*lambda= speed of waves. 
Thanks for the help!