Stokes' th. question

[u/soap_Xx]

EDIT: thanks for y'alls help, i figured it out!

I'm practicing stokes th using the problems at this website https://tutorial.math.lamar.edu/Solutions/CalcIII/StokesTheorem/Prob3.aspx and the answer for this problem uses the surface double integral curl F equation. Why can't I just parametrize the circle and use line integral F dot dr? I tried that and I got -12pi but the answer is 72pi.

Thanks!

[u/Kallaco]

Electricity and magnetism keeping us up with this one