Radio Wave Interference between Two Antennas

[Irockonice14]

Homework Statement

Two antennas located at points A and B are broadcasting radio waves of frequency 99.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d= 12.40 m. An observer, P, is located on the x axis, a distance x= 58.0 m from antenna A, so that APB forms a right triangle with PB as hypotenuse. What is the phase difference between the waves arriving at P from antennas A and B? Now observer P walks along the x-axis toward antenna A. What is P's distance from A when he first observes fully destructive interference between the two waves? If observer P continues walking until he reaches antenna A, at how many places along the x-axis (including the place you found in the previous problem) will he detect minima in the radio signal, due to destructive interference?

Homework Equations

The Attempt at a Solution

I got part A, which is 2.718 rad

http://lon-capa.bd.psu.edu/res/msu/physicslib/msuphysicslib/75_Interf_Diffrac1/graphics/prob08a_antennas.gif

 

[berkeman]

Homework Statement

Two antennas located at points A and B are broadcasting radio waves of frequency 99.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d= 12.40 m. An observer, P, is located on the x axis, a distance x= 58.0 m from antenna A, so that APB forms a right triangle with PB as hypotenuse. What is the phase difference between the waves arriving at P from antennas A and B? Now observer P walks along the x-axis toward antenna A. What is P's distance from A when he first observes fully destructive interference between the two waves? If observer P continues walking until he reaches antenna A, at how many places along the x-axis (including the place you found in the previous problem) will he detect minima in the radio signal, due to destructive interference?

Homework Equations

The Attempt at a Solution

I got part A, which is 2.718 rad

http://lon-capa.bd.psu.edu/res/msu/physicslib/msuphysicslib/75_Interf_Diffrac1/graphics/prob08a_antennas.gif

I'm not able to see the image. Can you upload it as an attachment?