see attached image
The Attempt at a Solution
I'm not sure where to begin with this one. We did a similar problem with a half-wave antenna, where I=I_0 cos(2πz/λ) and it was centered at the origin, so cos = 1 when z = 0.
So here I figured if we place the antenna in the positive z, then sin will = 0 when z = 0, then max out half way and decrease back to 0. But i'm not really sure.
Could someone please nudge me in the right direction?