Question

Let f(x, y) = x² + xy + y². What is the direction of minimum rate of change at point (5,2)? (Enter a vector, using [,] brackets, such that the first coordinate (x-coordinate) is 1, 0, or -1.) Components of vector of minimum change direction are ​

Answer 1

Explanation:

To find the direction of minimum rate of change for the function f(x, y) = x² + xy + y² at the point (5, 2), we need to find the gradient vector (also known as the gradient or the vector of partial derivatives) and then find the direction orthogonal to the gradient vector, as this direction will have the minimum rate of change.

First, let's find the gradient vector by computing the partial derivatives of f(x, y) with respect to x and y:

∂f/∂x = 2x + y

∂f/∂y = x + 2y

Now, evaluate the gradient vector at the point (5, 2):

∇f(5, 2) = (2(5) + 2, 5 + 2(2)) = (12, 9)

The gradient vector is (12, 9). To find the direction orthogonal to the gradient vector, we can swap the x and y components and negate one of them. Since the question asks for a vector with an x-component of 1, 0, or -1, we'll negate the x-component:

Orthogonal vector = (-1, 12)

So, the direction of minimum rate of change at point (5, 2) is given by the vector [-1, 12].