Local versus absolute extrema. If you recall from single-variable calculus (calculus I), if a function has only one critical point, and that critical point is a local maximum (or say local minimum), then that critical point is the global/absolute maximum (or say global/absolute minnimum). This fails spectacularly in higher dimensions (and thereís a famous example of a mistake in a mathematical physics paper because this fact was not properly appreciated.) You will compute a simple example in this problem. Let f(x; y) = e 3x + y 3 3yex . (a) Find all critical points for this function; in so doing you will see there is only one. (b) Verify this critical point is a local minimum. (c) Show this is not the absolute minimum by Önding values of f(x; y) that are lower than the value at this critical point. We suggest looking at values f(0; y) for suitably chosen y

Answers

Answer 1

Answer:

Step-by-step explanation:

Given that:

a)

[tex]f(x,y) = e^{3x} + y^3 - 3ye^x \\ \\ \implies \dfrac{\partial f}{\partial x} = 0 = 3e^{3x} -3y e^x = 0 \\ \\ e^{2x}= y \\ \\ \\ \implies \dfrac{\partial f}{\partial y } = 0 = 3y^2 -3e^x = 0 \\ \\ y^2 = e^x[/tex]

[tex]\text{Now; to determine the critical point:}[/tex]- [tex]f_x = 0 ; \ \ \ \ \ f_y =0[/tex]

[tex]\implies e^{2x} = y^4 = y \\ \\ \implies y = 0 \& y =1 \\ \\ since y \ne 0 , \ \ y = 1, \ \ x= 0\\\text{Hence, the only possible critical point= }(0,1)[/tex]

b)

[tex]\delta = f_xx, s = f_{xy}, t = f_{yy} \\ \\ . \ \ \ \ \ \ \ \ D = rt-s^2 \\ \\ i) Suppose D >0 ,\ \ \ r> 0 \ \text{then f is minima} \\ \\ ii) Suppose \ D >0 ,\ \ \ r< 0 \ \text{then f is mixima} \\ \\ iii) \text{Suppose D} < 0 \text{, then f is a saddle point} \\ \\ iv) Suppose \ D = 0 \ \ No \ conclusion[/tex]

[tex]Thus \ at (0,1) \\ \\ \delta = f_{xx} = ge^{3x}\implies \delta (0,1) = 6 \\ \\ S = f_{xy} = -3e^x \\ \\ \implies S_{(0,1)} = -3 \\ \\ t = f_{yy} = 6y \\ \\[/tex]

[tex]\implies t_{0,1} = 6[/tex]

[tex]Now; D = rt - s^2 \\ \\ = (6)(6) -(-3)^2[/tex]

[tex]= 36 - 9 \\ \\ = 27 > 0 \\ \\ r>0[/tex]

[tex]\text{Hence, the critical point} \ (0,1) \ \text{appears to be the local minima}[/tex]

c)

[tex]\text{Suppose we chose x = 0 and y = -3.4} \\ \\ \text{Then, we have:} \\ \\ f(0,-3.4) = 1+ (-3.4)^3 + 3(3.4) \\ \\ = -28.104 < -1[/tex]

[tex]\text{However, if f (0,1) = 1 +1 -3 = -1 \\ \\ f(0,-3.4) = -28.104} < -1} \\ \\ \text{This explains that} -1 \text{is not an absolute minimum value of f(x,y)}[/tex]


Related Questions

What is the vertex of the parabola

Answers

Answer:

lallalalaal hiiiiii

Step-by-step explanation:

The standard form is written as y = ax ^2 + b + c

Using the given equation:

A = -5, b = 30 and c = 7

The x value of the vertex = -b/ 2/a = -30/2(-5) = -30/-10 = 3

To find the y value replace x with the x value and solve for y:

Y = -5(3)^2 + 30(3) + 7

Y = -45 + 90 + 7

Y = 52

The vertex is (3,52)

The answer is G

whoever gets this correct first gets brainlest!!

Answers

D. f(x)=4 (5/2)^x

Are really good tool for graphing problems is Demos.com

how long will it take with 0.5kW power rating to do 1500J of work?

3 seconds
3 microseconds
3 minutes
0.3 seconds ​

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Try finding it in this https://www.uplifteducation.org/cms/lib01/TX01001293/Centricity/Domain/273/ENERGY%20CLIMATE%20PROBLEMS-SOL.pdf

Will give brainliest

Find the area of the following
triangle:
5 cm
10 cm
A= [?] cm2
Enter the exact answer as a decimal.

Answers

Answer:

25

Step-by-step explanation:

a=1/2bh

a=1/2(5)(10)

a=1/2(50)

a=25

Given the data set, calculate the median
{9, 3, 1, 8, 3, 6}

Answers

Answer:

4.5

Step-by-step explanation:

The median we know is the middle number of a set of numbers. Putting the set in least to great order, we have (1, 3, 3, 6, 8, 9). The middle number here is 3 and 6. We take the mean of 3 and 6, (3+6)/2 which gives us 4.5 and that is our answer.

Answer:

4.5

Step-by-step explanation:

i took the test

What is the solution for this equation?
A.X=2
B. X = 4
C. X=8
D. x = 12

Answers

The right side equals 12 so the left side needs to equal 12

Subtract the 4 circles:

12-4 = 8

There are 2 x’s so 8/2 = 4

X = 4

The answer is B. X = 4

A chocolate shop sells chocolates with a variety of different fillings.

hazelnut 68
caramel 8
orange 8

What is the probability that a randomly selected chocolate will have caramel filling?

Write your answer as a fraction or whole number.

Answers

Answer:

There is a [tex]\frac{2}{21}[/tex] chance of picking caramel-filled chocolate.

Step-by-step explanation:

To set this up, you need to make it a fraction. The denominator of the fraction is how many total chocolates you can pick from. You can figure this out by adding all of the chocolate choices together:

68 hazelnut + 8 caramel + 8 orange = 84 chocolates.

The numerator is defined by the number of caramel chocolates, in this case it is 8. That means the fraction will look like:

[tex]\frac{8}{84}[/tex]

Now that can be simplified down. I divided the top and bottom both by 4 to get  [tex]\frac{2}{21}[/tex] and that is as far down as it can go. Therefore that is the probability you will get a caramel-filled chocolate.

will mark brianliest please help

Answers

Answer:

See below.

Step-by-step explanation:

7x^2 = 343                     Divide both sides by 7

7x^2/7 = 343/7

x^2 = 49                         Take the square root of both sides.

sqrt(x^2) = sqrt(49)

x = +/- 7

Answers

7- 7sqrt(49)- sqrt(49)

I think the last two are kind of iffy. I'm not sure you can call them solutions, but the question probably assumes they are. If you use all four answers and get it wrong, them submit +7 and - 7.  

id- 5121786233 p/w- tepQ3w​

Answers

Answer:

ok

Step-by-step explanation:

Need to know angle 1, angle 2, angle 3

Answers

Answer: Step-by-step explanation:

angle 1=41°

angle 2=angle 1=41°

angle 3=180-2×41=98

What is the slope of a line that is perpendicular to the line whose equation is y=45x−3
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=
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x

3
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Answers

The slope of y=45-3 would be m=45

Lena is saving money to buy a game. So far she has saved $12, which is three-fourths of the total cost of the game. How much does the game cost?

Answers

Answer:

12(3/4)=9

12/4=3

3•3=9

Please help me please help no links

Answers

yeah i don’t know the answer but don’t press those links they are hackers

what's the x-intercept

Answers

Answer:

perhaps around 7.5?

Step-by-step explanation:

hope this is right :)

In a middle school of 80 students, 42 girls and 38 boys. What is the probability
that if two students were randomly chosen, the first is a boy and then a girl
sequentially?

Answers

Answer:

dont have idea

Step-by-step explanation:

have not studied that topic

Jaelyn uses 3 3/4 cups of flour to make 5 batches of pancakes. How many cups of flour she need to make 1 batch?


NO ANSWERS IN UNKNOWN SITES PLEASE OR I'LL REPORT IT!!!

Answers

Answer:

3/4

Step-by-step explanation:

Divide 3 3/4 by 5. 3 3/4 as an improper fraction is 15/4. 15/4 * 1/5 (divided by 5) is 3/4. :D dont report me

Please please please help no link no links no links

Answers

Answer:

400

Step-by-step explanation:

V = a² * h/3

Plug in your values:

V = 10² * 12/3

Then solve:

100 * 4 = 400

What is the value of the expression: x2 + y2 + x - y
when x = -1 and y = 3

Question 1 options:

6


8


12


16

Answers

Answer:    6

Step-by-step explanation:

x^2+y^2+x-y

Put x=-1 and y=1

(-1)^2+(3)^2+(-1)-(3)

1+9-1-3

10-4

6

3 Select the correct answer. 52 + 51 + 6 For the rational equation, 1 + 3 = 1 what is a valid value of x? ОА. B. -1 O C. 2 O D. 3 Reset Next​

Answers

9514 1404 393

Answer:

  B.  -1

Step-by-step explanation:

  [tex]\dfrac{x^2 +5x +6}{x+3}=1\qquad\text{given}\\\\\dfrac{(x+2)(x+3)}{x+3}=1\qquad\text{factor}\\\\x+2=1\qquad x\ne-3\qquad\text{cancel factors}\\\\x=-1\qquad\text{add $-2$}[/tex]

The only valid value of x is -1.

Can someone help with number 1 please?

Answers

A
A=l x w
6/10 divided by 3/4 is 4/5

VERY EASY, WILL GIVE 50 POINTS FOR CORRECT ANSWER ASAP AND WILL GIVE BRAINLIEST.

Answers

The answer is d. You are welcome

Find the product of (x + 3)(x − 3).

x2 − 6x + 9
x2 + 6x + 9
x2 + 9
x2 − 9

Answers

(x+3)(x-3)=
x^2-3x+3x-9=
x^2-9

Step-by-step explanation:

[tex](x + 3)(x - 3) \\ = {x}^{2} - 3x + 3x - 9 \\ = {x}^{2} - 9[/tex]

#CMIIW

56 + 72 = ( + )
help plz

Answers

Answer:

128 = +

Step-by-step explanation:

56 + 72  = 128 (+)

Which of the following exam scores should lead to the better grade? Explain your answer. (4 points)
A score of X = 55 on an exam that has a mean of 60 and a standard deviation of 5.

B. A score of X = 40 on an exam that has a mean of 50 and a standard deviation of 20.

Answers

Based on the z-score calculations, score A with a score of X = 55 should lead to the better grade.(option-a)

For score A with X = 55, the z-score can be calculated as:

z = (X - mean) / SD = (55 - 60) / 5 = -1

For score B with X = 40, the z-score can be calculated as:

z = (X - mean) / SD = (40 - 50) / 20 = -0.5

The z-score represents the number of standard deviations that a score is above or below the mean. A negative z-score means that the score is below the mean.

Since a z-score of -1 is greater than a z-score of -0.5, score A with X = 55 would be the better score. This is because score A is closer to the mean (60) than score B (50), and it has a smaller standard deviation (5) than score B (20). The lower standard deviation means that scores are more tightly clustered around the mean, making it more difficult to obtain a score that is much higher or lower than the mean.(option-a)

For such more questions on calculation

https://brainly.com/question/17145398

#SPJ8

This test will not impact your grade.
Exam
5
Shot
1.38
Find the missing side. Round
to the nearest tenth.
S
02
17
у
SC
440
Х
x= [?]
Enter

Answers

Answer:

if i am not wrong is 119

Step-by-step explanation:

I did it like this:

I took 44 + 17= 61

And then I took 180-61= 119

Dory can run 3.25 miles every hour. How long will it take her to run a race that is
16 1/4 miles long?

Answers

Answer:

it would take her 5 hours

Step-by-step explanation:

16 1/2 divided by 3.25 is 5

Brainliest plz

12. Draw an acute scalene triangle. Describe
the angles and sides of the triangle.
show
work.

Answers

Try googling this it will give you some examples and definitions.

https://mathbitsnotebook.com/Geometry/SegmentsAnglesTriangles/SATTriangleTypes.html

The function m is given in three equivalent forms.
Which form most quickly reveals the zeros (or "roots") of the function?
Choose 1 answer:
B
m(x) = -2x² +24x54
-
m(x) = -2(x - 6)² + 18
m(x) = -2(x - 3)(x-9)
Write one of the zeros.

Answers

Answer:

m(x) = -2(x - 3)(x - 9)

One of the zeros of the function is x = 3

Step-by-step explanation:

The form that most quickly reveals the zeros (or "roots") of the function is:

m(x) = -2(x - 3)(x - 9)

To find the zeros of the function, we set m(x) equal to zero:

-2(x - 3)(x - 9) = 0

From this equation, we can see that the zeros (roots) of the function occur when either (x - 3) equals zero or (x - 9) equals zero. Solving these equations gives us the zeros:

x - 3 = 0

x = 3

x - 9 = 0

x = 9

Therefore, one of the zeros of the function is x = 3.

Hope this helps!

When two 6-sided dice are rolled, there are 36 possible outcomes. Find the probability that the sum is 8

Answers

Answer:

5/36

Step-by-step explanation:

Probability is the outcome that a  event will occur

Probability = Expected outcome/Total outcome

Since two sided dice are rolled, the total outcome will be expressed as;

Total outcome = 36

Since we are to find the probability that the sum is 8, the values that gives a sum of 8a re;

(2,6)(6,2), (5, 3), (3,5), (4, 4)

The expected outcome = 5

Probability = 5/36

Hence the probability that the sum is 8 is 5/36

Andrew is shooting arrows at a target.
The experimental probability that one will hit a bulls eye is 1/4. If he shoots 60 arrows, how many times can he expect to hit a bulls eye?

Answers

Answer:

15

Step-by-step explanation:

60/4 = 15

So, Andrew would probably hit a bullseye 15 times.

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