1. The figure shows two point sources S1 and S2 that emit sound of wavelength λ = 1.8 m. The emissions are isotropic and in phase, and the separation between the sources is d = 18.0 m. At any point P on the x axis, the wave from S1 and the wave from S2 interfere. Start with P very far away (x = infin). As you then move P in along the x axis toward the origin, (a) does the phase difference between the waves increase or decrease? At what distance x do the waves have a phase difference of (b) 0.50λ, (c) 1.00λ, and (d ) 1.50λ? The diagram: (d is the distance from S1 to S2) y | | S1---------P-----> x | | | S2 | | 2. Fully Destructive interference phi = (2m+1)pi, Fully constructive interference phi=m(2pi), deltaL=sqrt(324+x^2)-x 3. The attempt at a solution Using the above equation of deltaL=sqrt(324+x^2)-x, I obtained the answers 161.5m, 80m, and 52.5 meters. sqrt(324+x^2) - x= 1 ,sqrt(324+x^2)-x=2, and sqrt(324+x^2)-x= 3 I'm confused as to why my answers are incorrect, I thought when the phase constants were 0.5lambda,1lambda, and 1.5lambda, the distance associated with these were 1,2, and 3. I know that my equation is correct from pythag, but im not 100% sure about my x value. Any assistance is greatly appreciated. Thanks in advance.