(1 point)
Calculate the directional derivative of f(x, y) = cot-'(xy) in the direction of v = -4i + 5j at the point P = (0.5, 0.5).
Remember to normalize the direction vector.
DS(0.5, 0.5) =

Answers

Answer 1

Looks like f(x, y) = cot⁻¹(xy), as in the inverse cotangent.

If you're like me and you don't remember the derivative of the inverse trig functions, we can derive it as follows. Let y = cot⁻¹(x), so that for appropriate x we can write cot(y) = x. By the chain rule, differentiating both sides gives

-csc²(y) y' = 1

y' = -sin²(y) = -sin²(cot⁻¹(x)) = - 1 / (x² + 1)

Next, recall that the derivative of a function f(x, y) at a point (a, b) in the direction of a vector v is given by

f(a, b) • v

Compute the gradient ∇ f(x, y) :

f(x, y) = - y / ((xy)² + 1) i - x / ((xy)² + 1) j

At the point P, we have

f(x, y) = - 8/17 i - 8/17 j

So, the derivative of f at P along v = - 4 i + 5 j is

(- 8/17 i - 8/17 j) • (- 4 i + 5 j) = - 8/17


Related Questions

What is the justification for step 2 in the solution process?16-5x=1-4x; -5x=-4x-15; -x=-15

Answers

Answer:

Addition Property Of Equality

Step-by-step explanation:

The variable was isolated on the left side of the equation by adding 4x to both sides. This is justified by the addition property of equality.

Step 1: -5x = -4x -15

Step 2: -x = -15

Answer:

the addition property of equality

Step-by-step explanation:

The variable was isolated on the left side of the equation by adding 4x to both sides. This is justified by the addition property of equality.

3x+x√3-2=0. Find value of x​

Answers

[tex] \sf \: 3x + x \sqrt{3} - 2 = 0 \\ \\ \sf \longrightarrow 3x + \sqrt{3} x = 2 \\ \\ \sf \longrightarrow \sqrt{3}x ( \sqrt{3} +1 ) = 2 \\ \\ \sf \longrightarrow \sqrt{3} x = \frac{2}{ \sqrt{3} + 1 } \\ \\ \sf \longrightarrow x = \frac{2}{ \sqrt{3}( \sqrt{3} + 1) } \\ \\ \sf \longrightarrow x = \frac{2}{3 + \sqrt{3} } \\ \\ \tt{You\:can\:stop\:here\:if\:you\:\bold{don't}\:want\:to }\\ \tt{ \:simplify\:in\:decimal\:form.}\\ \\ \sf \longrightarrow x = \frac{2(3 - \sqrt{3} )}{(3 + \sqrt{3})(3 - \sqrt{3} )} \\ \\ \sf \longrightarrow x = \frac{6 - 2 \sqrt{3} }{ {3}^{2} - {( \sqrt{3}) }^{2} } \\ \\ \sf \longrightarrow x = \frac{6 - 2(1.732)}{9 - 3} \\ \\ \sf \longrightarrow x = \frac{2.536}{6} \\ \\ \leadsto \underline{\boxed{\sf{\pink{x \approx 0.4226}}}}[/tex]

How could you informally prove to your friend that you have been working with a trainer at the gym.
You can show your gym bill.
You can show your membership card.
You can demonstrate some of the exercises that your trainer taught you.
You can show your before and after charts for your muscle mass.

Answers

Answer:

You can demonstrate some of the exercises that your trainer taught you

Step-by-step explanation:

The rest of the options are too formal.

You can demonstrate some of the exercises that your trainer taught you. The correct option is C.

what is convincing communication?

Persuasive communications include a variety of attributes designed to increase persuasions, such as an appealing source, a message with convincing arguments, or efforts to make the topic seem personally relevant to the audience.

You can prove to your friend that you have been working with a trainer at the gym by demonstrating some of the exercises that your trainer taught you.

Therefore, you can demonstrate some of the exercises taught to you by your trainer. C is the correct answer.

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Reese wants to organize a party and decides to save money for it.He calculates that he needs $420 in 9 weeks.He already has $60

Answers

Start by creating an equation. You’ll need a variable to represent what is earned per week, for example x.

So,
420=60+9x
(Since he already has 60)
Subtract the 60 from 420 to begin isolating the variable
This gives you
360=9x
Divide both sides by 9 to completely isolate the variable
This gives you
40=x
So, he needs to save up $40 each week

A box of LED light bulbs was tested to see how long the light bulbs last. The standard deviation of the light bulb lifetime data was five years. Which of the following is the best interpretation of this value?

Fifty percent of the light bulb lifetime data is below five years.
The difference between the longest and shortest light bulb lifetime was five years.
The lifetime of the light bulbs typically varies by about five years from the mean.
The middle half of the light bulb lifetime data has a range that is five years wide.

Answers

The difference between the longest and shortest light bulb lifetime was five years is correct interpretation so option (B) will be correct.

What is the standard deviation?

The square root of the variance is used to calculate the standard deviation, a statistic that expresses how widely distributed a dataset is in relation to its mean.

In other meaning, standard deviation shows the deviation of the value of data from the mean.

Standard deviation is how much-given data is deviate from the mean of it.

So the difference between the longest to shortest gives an idea about this deviation.

Hence "The difference between the longest and shortest light bulb lifetime was five years is a correct interpretation".

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in need the proofs and statements

Answers

Answer:

Since we are given that angle Y = angle Z

The magnitude of the angles will also be equal

∠Y = ∠Z

(x + 10) = (2x - 90)

90 + 10 = 2x - x

100 = x

Find the solution of the system of equations

4x-8y=44
2x+4y=-6

Answers

It is easiest to solve this system by elimination.

4x-8y=44

(2x+4y=-6) -2    ----> multiply the second equation by -2 to create equations where the x coefficients are opposites

     4x-8y=44

(+) -4x-8y=12

-16y=56

y = -7/2

now substitute the value of y into one of the above equations and solve for x

4x – 8(-7/2) = 44

4x + 28 = 44

4x = 16

X = 4

So, the solution is (4, -7/2)

The solution of the  system of equations 4x-8y=44 and 2x+4y=-6is (4, -3.5).

What is Equation?

Two or more expressions with an Equal sign is called as Equation.

The given system of equation is 4x-8y=44 ...(1)

and 2x+4y=-6...(2)

To eliminate y term we have to multiply equation 2 with 2.

4x+8y=-12..(3)

Now add equation 1 and 3.

4x-8y+4x+8y=44-12

8x=32

Divide both sides by 8

x=4

Now plug in x value in equation 1

4(4)-8y=44

16-8y=44

Subtract 16 from both sides

-8y=44-16

-8y=28

Divide both sides by 8

y=-28/8

y=-7/2

=-3.5

Hence, the solution of the  system of equations is (4, -3.5).

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A cell phone company charges $25 per month, plus $0.10 per text message sent. Before taxes, Susie’s bill was $80 for 3 months of service. How many text messages did Susie send during those 3

Answers

50 text messages

let m = the number of months
let t = each message sent

25m + 0.1t = 80

plug 3 in for m (because 3 months)
25(3) + 0.1t = 80

simplify
75 + 0.1t = 80

subtract 75 from 80
0.1t = 5

divide 5 by 0.1
t = 50

answer: 50 text messages

Write the equation of a line that passes through the points (−3, 7) and (3, 3)
y=−2/3x+5

y=2/3x+1

y=−2/3x+9

y=2/3x+9

Answers

Step-by-step explanation:

You can write an equation of a line conveniently by point-slope form. It's in the form of [tex]y -a = m(x -b)[/tex] where [tex](b,a)[/tex] is the coordinates of a point that's on the line and [tex]m[/tex] is the slope of the line.

Now choose a point (It doesn't really matter which one) and plug that in the equation. I'll choose [tex](-3,7)[/tex] where [tex]a = 7[/tex] and [tex]b = -3[/tex]

[tex]y -a = m(x -b) \\ y -7 = m(x -(-3)) \\ y -7 = m(x +3)[/tex]

The next thing we have to do now is finding the slope, [tex]m[/tex], where it's equal to [tex]\frac{y_{2} -y_{1}}{x_{2} -x_{1}}\\[/tex]. I'll make [tex](-3,7)[/tex] point 1 and [tex](3,3)[/tex] point 2.

[tex]m = \frac{3 - 7}{3 -(-3)} \\ m = \frac{3 - 7}{3 +3} \\ m = \frac{-4}{6} \\ m = -\frac{2}{3}[/tex]

Now let's plug that to our equation.

[tex]y -7 = m(x +3) \\ y -7 = -\frac{2}{3}(x +3)[/tex]

Now we have the equation but out of all the choices it seemed that all of them are in slope-intercept form all you have to do now is make our equation rewrite it in slope-intercept form.

[tex]y -7 = -\frac{2}{3}(x +3)\\ y -7 = -\frac{2}{3}x -\frac{2}{3}(3) \\ y - 7 = -\frac{2}{3}x -2\\ y = -\frac{2}{3}x +5[/tex]

Answer:

[tex]y = -\frac{2}{3}x +5\\[/tex] is your equation.

Write the polynomial in standard form. Identify the degree and leading coefficient of the polynomial. Then classify the polynomial by the number of terms.

6c2+2c4−c

Answers

Answer:

46;&74)474:&48&4:&48&

Step-by-step explanation:

For example if you have a function f(x) = x - 1, then x = 1 is a zero of this function because using it as x gives 1 - 1 = 0. The Riemann Zeta function has some zeros that are easy to find which are of little interest but there are some other ones that are harder to find which is why the are called non-trivial.

Beth bought 35¢ stamps and 15¢ stamps at the post office. If she purchased 60 stamps at a cost of $17, how many of each kind did she buy?

Answers

Answer:

She buys 20 Stamps of $0.15 and 40 Stamps of $0.35.

Step-by-step explanation:

40 x 0.35 = 14

20 x 0.15 = 3

$14 + $3 = $17

40 ($0.35) + 20 (0.15) = 60 stamps

Please help me guys!!!

Answers

The answe is D bc 20-10 both have an x and 5 doesn’t so ur subtracting like it said and then dividing 5 since it doesn’t have the same symbol

Factor the following expression completely. 4b^8-61b^4+225

Answers

Answer is shown in the picture

Functions and their Properties

Practice
Need help​

Answers

Answer:

[tex]g(n-7)=\frac{n^{2}-14n+43}{7n-49}[/tex]  → (a)

Step-by-step explanation:

We need to evaluate g(n - 7), where

[tex]g(x)=\frac{x^{2}-7}{7x}[/tex]

Replace x by (n - 7) to evaluate it

x = (n - 7)

∴ [tex]g(n-7)=\frac{(n-7)^{2}-6}{7(n-7)}[/tex]

→ Let us find (n - 7)²

∵ (n - 7)² = (n - 7)(n - 7) = (n)(n) + (n)(-7) + (-7)(n) + (-7)(-7)

∴ (n - 7)² = n² + (-7n) + (-7n) + 49 = n² + -14n + 49

(n - 7)² = n² - 14n + 49

→ Find 7(n - 7)

∵ 7(n - 7) = 7(n) - 7(7)

7(n - 7) = 7n - 49

→ Now let us write then in the form above

∵ [tex]g(n-7)=\frac{n^{2}-14n+49-6}{7n-49}[/tex]

→ Add the like terms in the numerator

∴  [tex]g(n-7)=\frac{n^{2}-14n+43}{7n-49}[/tex]

The correct answer is (a)

What is the solution to the equation? 13+x=74

x=-6 1/4

x=-6 1/4

x =20

x=21​

Answers

you subtract 13 from both sides, leaving us with:
x = 74 - 13
x = 61. this answer has not been listed, but it is correct.

maybe you made a typo when writing the actual problem down? if not, 61 is the answer.

4x -2 + 5x + 6
What does this equAl

Answers

Answer:

9x + 4

Step-by-step explanation:

Step 1: Write expression

4x - 2 + 5x + 6

Step 2: Combine like terms (x)

9x - 2 + 6

Step 3: Combine like terms (constants)

9x + 4

Answer:

9x + 4

Step-by-step explanation:

Could someone please help with this math problem??!

Answers

I agree with this person that will be a good use

I need help with number 8 and please explain

Answers

Answer:

No

The sides of the triangle do not satisfy the Pythagorean Theorem.

Step-by-step explanation:

If we are given the three sides to a triangle, and we are asked to find out if it is a right triangle, we will have to see if the sides of the triangle satisfies the Pythagorean Theorem. The Pythagorean Theorem is:

a² + b² = c²

where c is the hypotenuse and a and b are the other two sides.

So we can see from the image that 28 would be the length of the "hypotenuse" and 19 and 20 would be the lengths of the other two sides. Lets see if these values satisfy the Pythagorean Theorem:

19² + 20² = 28²

361 + 400 = 784

761 ≠ 784

So no, the triangle is not a right triangle because the sides does not satisfy the Pythagorean Theorem.

I hope you find my answer and explanation to be helpful. Happy studying.

Choose the equation below that represents the line passing through the point (2, -5) with a slope of -3.
y = -3% - 13
Oy=-3x + 13
Oy=-3x + 1
Oy=-3x + 11

Answers

Answer:

D

Step-by-step explanation:

Slope

All answers agree that the slope = - 3

y intercept

So far what you know is that the line is

y = -3x + b

The point shows that

5 = -3*2 + b                    Combine right

5 = -6 + b                        Add 6 to both sides

5 + 6 = -6+6 + b             Combine

11 = b

So the y intercept = 11

Answer: y = -3x + 11              D

write the given equation of a line that passes through two given points (0,1) and (2,2)

Answers

Answer:

m=slope  y = intercept

m= y2-y1 / x2-x1

       2-1   /   2-0  =  1 /2

now pick one of the points and put in for y and x

use (2,2)    2= 1/2(2) +b

                  2=1 + b

              2-1 =1-1 +b   subtract 1 from each side

                  1 = b   This is your y intercept

Step-by-step explanation:

The equation of the line passing through points  (0,1) and (2,2) will be y = ( 1 / 2) x + 1

What is an equation of the line?

An equation of the line is defined as a linear equation having a degree of one. The equation of the line contains two variables x and y. And the third parameter is the slope of the line which represents the elevation of the line.

The general form of the equation of the line:-

y = mx + c

m = slope

c = y-intercept

Slope = ( y₂ - y₁ ) / ( x₂ - x₁ )

Slope= 2-1   /   2-0  =  1 /2

Now pick one of the points and put in for y and x use (2,2).

2= 1/2(2) +b

2=1 + b

2-1 =1-1 +b   subtract 1 from each side

1 = b   This is your y-intercept

The equation will be written as:-

y = ( 1 / 2) x + 1

Therefore, the equation of the line passing through points  (0,1) and (2,2) will be y = ( 1 / 2) x + 1.

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Which of the following have a value equal to |37|? Select all that apply.

A. -37
B. 1-371
C. 0
D. -(-37)
E. 37

Answers

Answer:

a and e

Step-by-step explanation:

Answer:

A, D, and E

Step-by-step explanation:

IN THE CENTRAL CITY GRAND PRIX, OUT OF 50 CARS THAT STARTED THE RACE, 12
OF THEM FINISHED. WHAT PERCENT OF THE CARS FINISHED THE RACE? WHAT
PERCENT DID NOT FINISH THE RACE?
I need a step by step explanation please !!!

Answers

Answer:

24% finished, 76% did not

Step-by-step explanation:

12cars/50 total +24%, and then just subtract 100% by the 24 to get 76% for the remaining percent

Answer:

24% finished and 76% did not

Step-by-step explanation:

you have the ratios:

12/50 and 38/50

These have to be turned into percentages so they need to have a denominator of 100

to do this, figure out what you have to multiply the denominator by to get 100

In this case, 50 times 2 is equivalent to 100.

Then, whatever you multiplied the denominator by, you multiply the numerator by

In this case, 12 times 2 is 24 and 38 times 2 is 76

Once you have the end products, take the numerator and add a percentage sign to it

Chat me if you have anymore questions

HELPPPP!!!! PLEASEEE!!!
Which statement below is true?
A. If p → q is true, then q → p is true.
B. If p → q is true and p is true, then q is true.
C. If p → q and q → r are true, then q → p is true.
D. If p → q and q → r are true, then r → p is true.

Answers

Answer:

D is correct

Step-by-step explanation:

p=q  then q is the same as p and if r=p that is true

What is 9/10 divided by 3/4?

Answers

Answer:

6/5

Step-by-step explanation:

hi! when dividing fractions, we use the KCF rule, which stands for keep,change,flip. we keep the first fraction the same, change the division symbol to multiplication, and flip the second fraction to its reciprocal. therefore, we now have:

9/10 * 4/3

now, we can multiply the numerators and denominators.

36/30

we can simplify this.

6/5

do you agree that the equation (x-4)²=9 can be solved both by factoring and extracting square roots? ​

Answers

Given parameters:

  Equation:

          (x-4)²=9

Problem, solve the equation by factoring and extracting the root

Solution:

    Given equation:

                  (x-4)²=9

         subtract 9 from both sides to equate to zero;

                (x-4)² - 9 = 0

                (x -4)² - 3² = 0

  Now, this is similar to the concept of difference of two squares;

          x² - y² = (x + y)(x-y)

                     

Here x  = x-4 and y = -3

  So input and solve;

              (x - 4 -3)(x - 4 -(-3)) = 0

              (x - 7)(x - 4+3) = 0

              (x -7)(x -1) = 0

S0,

             x - 7 = 0 or x-1 = 0

             x = 7 or 1

If we extract the square roots;

          (x-4)² = 9

         √(x-4)² = √9

              x - 4 = 3

              x  = 4 + 3 = 7; this is not the only solution to the problem

So we cannot solve it by extracting the square root.

The solutions by checking are incorrect for the second solution, hence the expression cannot be solved by extracting the square root. The equation can only be solved by factoring

Given the expression;

(x-4)²=9

This expression can be solved by factoring

Factoring the expression on the left hand side

(x-4)(x-4)=9

x²-4x-4x+16 = 9

x² - 8x + 16 - 9 = 0

x² - 8x + 7 = 0

x² -x - 7x + 7 = 0

x(x-1) -7(x-1) = 0

x-7 = 0 and x - 1 = 0

x = 7 and 1

This shows that the expression can be solved by factoring

The other way is by squaring both sides

(√x-4)² = ±√9

x - 4 =±√9

x = -9+4 and x = 9 + 4

x = -5 and 13

Since the solutions by checking are incorrect for the second solution, hence the expression cannot be solved by extracting the square root

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Two trees standing side by side in the sunlight one is 50 feet tall and the other is 20 feet tall if the taller tree casts a 18-foot shadow, what is the length in feet of the shadow of the shorter tree

Answers

Given:

Length of taller tree = 50 feet

Length of shorter tree = 20 feet

Length of shadow of taller tree = 18 feet

To find:

The length of shadow of shorter tree.

Solution:

Since, two trees standing side by side in the sunlight, therefore the length of trees are proportional to their shadows.

Let the length of shadow of shorter tree be x feet.

Using the given information, we get

[tex]\dfrac{50}{18}=\dfrac{20}{x}[/tex]

By cross multiplication, we get

[tex]50\times x=20\times 18[/tex]

[tex]50x=360[/tex]

[tex]x=\dfrac{360}{50}[/tex]

[tex]x=7.2[/tex]

Therefore, the length of shadow of shorter tree is 7.2 feet.

What are the solution(s) of the quadratic equation 98 – x2 = 0?

Answers

Answer:

49

Step-by-step explanation:

98-x2=0

-98    -98

[tex]\frac{x2}{2}[/tex]     [tex]\frac{98}{2}[/tex]

    49

The average temperature at the South Pole is -49.62°C, and the average temperature at the North Pole is -34.68°C. How much higher is the average temperature at the North Pole than at the South Pole?
A.
-84.3°C
B.
-14.94°C
C.
14.94°C
D.
84.3°C

Answers

Answer:

i am pretty sure it's -14.92

Step-by-step explanation:

Answer:

B!!!

Step-by-step explanation:

Is the function even, odd, or neither?

Answers

Answer:

A function with a graph that is symmetric about the origin is called an odd function. Note: A function can be neither even nor odd if it does not exhibit either symmetry. For example, f(x)=2x f ( x ) = 2 x is neither even nor odd

Step-by-step explanation:

A survey found that 12 out of every 15 people like eating at restaurants. If 500 people surveyed like eating at restaurants, how many people took the survey?
if the answers are 600 | 625 | 15 | 500

[URGENT]

Answers

Answer:

625

Step-by-step explanation:

625

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