Mathematics College

Find the absolute extrema of the function over the region R. (In each case, R contains the boundaries.) Use a computer algebra system to confirm your results. (Order your answers from smallest to largest x, then from smallest to largest y.)
f(x, y) = x2 − 4xy + 5
R = {(x, y): 1 ≤ x ≤ 4, 0 ≤ y ≤ 2}

Answers

Answer 1

f(x, y) = x ² - 4xy + 5

has critical points where both partial derivatives vanish:

∂f/∂x = 2x - 4y = 0 ==> x = 2y

∂f/∂y = -4x = 0 ==> x = 0 ==> y = 0

The origin does not lie in the region R, so we can ignore this point.

Now check the boundaries:

• x = 1 ==> f (1, y) = 6 - 4y

Then

max{f (1, y) | 0 ≤ y ≤ 2} = 6 when y = 0

max{f (1, y) | 0 ≤ y ≤ 2} = -2 when y = 2

• x = 4 ==> f (4, y) = 12 - 16y

Then

max{f (4, y) | 0 ≤ y ≤ 2} = 12 when y = 0

max{f (4, y) | 0 ≤ y ≤ 2} = -4 when y = 2

• y = 0 ==> f (x, 0) = x ² + 5

Then

max{f (x, 0) | 1 ≤ x ≤ 4} = 21 when x = 4

min{f (x, 0) | 1 ≤ x ≤ 4} = 6 when x = 1

• y = 2 ==> f (x, 2) = x ² - 8x + 5 = (x - 4)² - 11

Then

max{f (x, 2) | 1 ≤ x ≤ 4} = -2 when x = 1

min{f (x, 2) | 1 ≤ x ≤ 4} = -11 when x = 4

So to summarize, we found

max{f(x, y) | 1 ≤ x ≤ 4, 0 ≤ y ≤ 2} = 21 at (x, y) = (4, 0)

min{f(x, y) | 1 ≤ x ≤ 4, 0 ≤ y ≤ 2} = -11 at (x, y) = (4, 2)

Related Questions

In a food preference experiment, 80 lizards were given the opportunity to choose to eat one of three different species of insects. The results showed that 33 of the lizards chose species A, 12 chose species B, and 35 chose species C. They conducted a Chi-squared analysis to test for equal preference. What are the Null and Alternate hypothesis for this test

Answers

Answer:

H0 : The variables are independent

H1 : The variables are not independent

Step-by-step explanation:

In a Chisquare test ; The null hypothesis is used to lay claim that the variables are independent, that is no relationship exists between the categorical variables in the population while the alternative hypothesis negates the null thus claiming that the variables aren't independent.

The null hypothesis, H0 : The variables are independent, A = B = C

The alternative hypothesis ; H1 : The variables are not independent, A ≠ B ≠ C

Leanne is planning a bridal shower for her best friend. At the party, she wants to serve 33 beverages, 33 appetizers, and 22 desserts, but she does not have time to cook. She can choose from 1313 bottled drinks, 77 frozen appetizers, and 1313 prepared desserts at the supermarket. How many different ways can Leanne pick the food and drinks to serve at the bridal shower

Answers

Answer:

She can pick the food and drinks in 780,780 different ways.

Step-by-step explanation:

The drinks, appetizers and desserts are independent of each other, so the fundamental counting principle is used.

Also, the order in which the beverages, the appetizers and the desserts are chosen is not important, which means that the combinations formula is used to solve this question.

Fundamental counting principle:

States that if there are p ways to do a thing, and q ways to do another thing, and these two things are independent, there are p*q ways to do both things.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

Beverages:

3 from a set of 13. So

[tex]C_{13,3} = \frac{13!}{3!10!} = 286[/tex]

Appetizers:

3 from a set of 7, so:

[tex]C_{7,3} = \frac{7!}{3!4!} = 35[/tex]

Desserts:

2 from a set of 13, so:

[tex]C_{13,2} = \frac{13!}{2!11!} = 78[/tex]

How many different ways can Leanne pick the food and drinks to serve at the bridal shower?

286*35*78 = 780,780

She can pick the food and drinks in 780,780 different ways.

∫[tex]\frac{x+2019}{x^{2}+9 }[/tex]

Answers

Split up the integral:

[tex]\displaystyle\int\frac{x+2019}{x^2+9}\,\mathrm dx = \int\frac{x}{x^2+9}\,\mathrm dx + \int\frac{2019}{x^2+9}\,\mathrm dx[/tex]

For the first integral, substitute y = x ² + 9 and dy = 2x dx. For the second integral, take x = 3 tan(z) and dx = 3 sec²(z) dz. Then you get

[tex]\displaystyle \int\frac x{x^2+9}\,\mathrm dx = \frac12\int{2x}{x^2+9}\,\mathrm dx \\\\ = \frac12\int\frac{\mathrm du}u \\\\ = \frac12\ln|u| + C \\\\ =\frac12\ln\left(x^2+9\right)[/tex]

and

[tex]\displaystyle \int\frac{2019}{x^2+9}\,\mathrm dx = 2019\int\frac{3\sec^2(z)}{(3\tan(z))^2+9}\,\mathrm dz \\\\ = 2019\int\frac{3\sec^2(z)}{9\tan^2(z)+9}\,\mathrm dz \\\\ = 673\int\frac{\sec^2(z)}{\tan^2(z)+1}\,\mathrm dz \\\\ = 673\int\frac{\sec^2(z)}{\sec^2(z)}\,\mathrm dz \\\\ = 673\int\mathrm dz \\\\ = 673z+C \\\\ = 673\arctan\left(\frac x3\right)+C[/tex]

Then

[tex]\displaystyle\int\frac{x+2019}{x^2+9}\,\mathrm dx = \boxed{\frac12\ln\left(x^2+9\right) + 673\arctan\left(\frac x3\right) + C}[/tex]

Find the area of the sector round your answer to the nearest 10th

Answers

Answer:

63.4

Step-by-step explanation:

Area of sector=pi*r^2*(theta/360)

Area of sector=pi*121*(60/360)

Area of sector=63.4

Geometry homework due tonightttt worth 50 points

Answers

Answer:

Angle 2 = 180 - 76 = 104 (linear pair)

angle 3 = 76 (vertically opposite angles)

angle 4 = 104(vertically opposite angles)

Answer:

m∠2 = 104°m∠3 = 76°m∠4 = 104°

Step-by-step explanation:

Concept:

Here, we need to know the idea of supplementary angles and linear pairs.

Supplementary angles are two angles or arcs whose sum is 180 degrees.

A linear pair of angles are formed when two lines intersect. Two angles are said to be linear if they are adjacent angles formed by two intersecting lines. The measure of a straight angle is 180 degrees.

Linear pair and supplementary angles are conveying the same meaning. However, linear pair is describing the "appearance" of the two angles as they form a line which is 180 degrees. On the other hand, supplementary angles are the properties stating two angles adds up to 180 degrees, but are not required to be together.

If you are still confused, you can refer to the attachment below for a graphical explanation.

Solve:

∠1 and ∠2 are linear pairs and supplementary to each other forming 180°

m∠2 = 180 - 76 = 104°

∠2 and ∠3 are linear pairs and supplementary to each other forming 180°

m∠3 = 180 - 104 = 76°

∠3 and ∠4 are linear pairs and supplementary to each other forming 180°

m∠4 = 180 - 76° = 104°

Hope this helps!! :)

Please let me know if you have any questions

A regular six sided die is to be rolled once what is the probability that a number less than three is rolled

Answers

Answer:

1/3

Step-by-stepi

White colour is painted in 2 ft wide which lies inside from both sides in the basketball court of length 78 ft and breadth 46 ft . find the area of the painted part.

Answers

Answer:

L1=78

W1=46

L2=78+4=82

W2=46+4=50

Area=L2×W2-L1×W1

82×50-78×46

Ans- 512ft^2

The firm had 15 billion VND of earnings before interest and tax (EBIT), corporate tax is 20%. The market price of stock is 60.000đ. Knowing that net income will be held 40% before using it for dividend. How much of the net income can be divided for shareholders?