Let [tex]f (x, y) = e^x^2 + 3e^y[/tex] . At the point (0, 1) find:
(a) a vector u such that the directional derivative [tex]D_u f[/tex] is maximum and write down this maximum value,
(b) a vector v such that [tex]D_v f = 0[/tex]
grad f / directional derivative formula
The Attempt at a Solution
I can find part (a), simply calculate the gradient vector, but part (b) I don't know what to do. The answer given is:
(b) Dv f is zero when v is tangent to the level curve passing through (0, 1), i.e. when v = i
(or some multiple of this).
I don't understand what this means.