In Exercises 7–10, use Theorem 13.9 to find the directional derivative of the function at P in the direction of v.

h(x, y) = e^-(x2+y2), P(0, 0), v = i + j

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THEOREM 13.9 Directional Derivative If f is a differentiable function of x and y, then the directional derivative of f in the direction of the unit vector u = cos i + sin ej is Duf(x, y) = f(x, y) cos 0 + f(x, y) sin 0.