9. How fast is the function f(x, y,=) = xsin(yz) increasing at the point (1, 3, 0,0) in the direction ?10. Circle the impossible expression(s). State whether the possible expressions are scalar or vector quantities. d . b x Z *(B . 2 ) d x b xc d x b . * (b x 2) d + (b . 2 )