Imagine that you have an opaque screen with three horizontal 1 very narrow parallel slits...

Imagine that you have an opaque screen with three horizontal 1 very narrow parallel slits in it. The second slit is a center-to-center distance a beneath the first, and the third is a distance 5a/2 beneath the first, (a) Write a complex exponential expression in terms of δ for the amplitude of the electric field at some point P at an elevation θ on a distant screen where δ = ka sin θ. Prove that

Verify that at θ =0,I(θ) = I (0).