F(x, y) = x2 + y2 + 4x − 4y, x2 + y2 ≤ 81 find the extreme values of f on the region described by the inequality.

The extreme values of a function are the minimum and the maximum values of the function.

The extreme values are: -8 and 131.91

The given parameters are:

Find the gradient of F(x,y)

Set to 0, to solve for x and y

So, the critical point is:

Also, we have:

Calculate the gradients

Equate the gradients as follows:

So, we have:

Make the subject, in the above equations

Equate the above equations, so we have:

Cross multiply

Subtract xy from both sides

Divide both sides by 2

Substitute in

Divide both sides by 2

Take square roots

Rationalize

Recall that:

So, we have:

The ordered pairs are:

Hence, the points are:

Substitute these values in

Hence, the extreme values of the function are: -8 and 131.91

Read more about extreme values at:

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134.6 us dollars

step-by-step explanation:

1 us dollar = 1.33 canadian dollars

so, 150 us dollars = 150 × 1.33 = $199.5.

in canada, the money mitchell spent = 20 canadian dollars.

remaining canadian dollars with him = 199.5 - 20 = 179.5.

after mitchell returned to us, he exchanged the remaining canadian dollars to us dollars.

179.5 canadian dollars = 179.5 × 0.75 = 134.6 us dollars.