Calculus 3 Lecture Notes, Section 11.4

The gradient of f(x, y) is the vector-valued function , provided both partial derivatives exist. Theorem 6.2: The Directional Derivative in Terms of the Gradient. If f(x, y) is differentiable and is any unit vector, then: Theorem 6.3: Properties of the Gradient. If f(x, y) is differentiable at the point (a, b), then: ................
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