# Wave interference

Discussion in 'Math' started by boks, Nov 12, 2008.

1. ### boks Thread Starter Active Member

Oct 10, 2008
218
0
If the amplitude of three intersecting waves is given by

$y(r,t) = \frac{A}{r}e^{i(kr-wt)}[1-2cos(kdsin\theta)]$

how can I then find the intensity at r = 200 m as a function of $\theta$?

I know that intensity is the square of the amplitude. Should I simply square y(r,t)? If I do, I get I as a function of t as well, because of the part $e^{i(kr-wt)}$.

2. ### mik3 Senior Member

Feb 4, 2008
4,846
67
If the waves have the same frequency then ωt=θ

Transform the exponential term into a polar representation (cos(x)+jsin(x)) and then find the modulus (amplitude) of the resulting complex number.

3. ### KL7AJ AAC Fanatic!

Nov 4, 2008
2,152
389
Analytic signals are SO much simpler to deal with, aren't they?

Eric