Use Stokes' theorem for both parts, which equates the surface integral of the curl to the line integral along the surface's boundary.
a. The boundary of the hemisphere is the circle 
in the plane 
, where the curl is 
. Green's theorem applies here, so that
which means the value of the line integral is 3 times the area of the circle, or 
.
b. The closed sphere has no boundary, so by Stokes' theorem the integral is 0.
The expansion of a perfect square is
In words, the square of a sum of two terms is the sum of the squares of the two terms (
and 
), plus twice the product of the two terms (
)
So, when determining if you have a perfect square trinomial, you should have two perfect squares. Note that they don't have to be the first and third term, since you can rearrange terms as you prefer.
Well if I did the math correctly it should be B) <span>9√5</span>
