Why is it 2π and not π?
Use the surface integral in Stokes' Theorem to calculate the circulation of the field F = xi + 3xj + zk around the curve C: the ellipse 9x^2 + y^2 = 2 in the xy-plane, counterclockwise when viewed from above.
∮F·dr = 2πT
C (Type an exact answer, using t as needed.)