(1 point)
Let $F(x, y, z) = (9xz^2, -3xyz, -7xy^3z)$ be a vector field and $f(x, y, z) = x^3y^2z$.
$\nabla f = (3x^2y^2z, 2x^3yz, x^3y^2)$
$\nabla \times F = (-21xy^2z + 3xy, -( -7y^3z - 18xz), -3yz)$
$F \times \nabla f = (-3x^4y^3z + 14x^4y^4z^2, 18x^4yz^3 + 9x^3y^3z^2, )$
$F \cdot \nabla f = 27x^3y^2z^2 - 6x^4y^2z^2 - 7x^4y^5z$