(1 point) Are the following statements true or false? False v 1. If u is a unit vector, then fu(a, b) is a vector. False v 2. fu (a, b) = 1IV f(a, b)Il. False v 3. If u is perpendicular to V f(a, b), then fu (a, b) = (0, 0). False v 4. The gradient vector V f(a, b) is tangent to the contour of f at (a, b). False v 5. If f(x, y) has fx(a, b) = 0 and fy(a, b) = 0 at the point (a, b), then f is constant everywhere. False v 6. V f(a, b) is a vector in 3-dimensional space. False V 7. Suppose fx(a, b) and fy(a, b) both exist. Then there is always a direction in which the rate of change of f at (a, b) is zero. True v 8. f; (a, b) is parallel to u