Let f be a function of two variables that has continuous partial derivatives and consider the points

A(8, 9),

B(10, 9),

C(8, 10),

and

D(11, 13).

The directional derivative of f at A in the direction of the vector AB is 9 and the directional derivative at A in the direction of

AC is 2. Find the directional derivative of f at A in the direction of the vector AD.

(Round your answer to two decimal places.)

Answers

Answer 1

Answer:

The directional derivative of f at A in the direction of [tex]\vec{u}[/tex] AD is 7.

Step-by-step explanation:

Step 1:

Directional of a function f in direction of the unit vector [tex]\vec{u}=(a,b)[/tex] is denoted by [tex]D\vec{u}f(x,y)[/tex],

[tex]D\vec{u}f(x,y)=f_{x}\left ( x ,y\right ).a+f_{y}(x,y).b[/tex].

Now the given points are

[tex]A(8,9),B(10,9),C(8,10) and D(11,13)[/tex],

Step 2:

The vectors are given as

AB = (10-8, 9-9),the direction is

[tex]\vec{u}_{AB} = \frac{AB}{\left \| AB \right \|}=(1,0)[/tex]

AC=(8-8,10-9), the direction is

[tex]\vec{u}_{AC} = \frac{AC}{\left \| AC \right \|}=(0,1)[/tex]

AC=(11-8,13-9), the direction is

[tex]\vec{u}_{AD} = \frac{AD}{\left \| AD \right \|}=\left (\frac{3}{5},\frac{4}{5} \right )[/tex]

Step 3:

The given directional derivative of f at A [tex]\vec{u}_{AB}[/tex] is 9,

[tex]D\vec{u}_{AB}f=f_{x} \cdot 1 + f_{y}\cdot 0\\f_{x} =9[/tex]

The given directional derivative of f at A [tex]\vec{u}_{AC}[/tex] is 2,

[tex]D\vec{u}_{AB}f=f_{x} \cdot 0 + f_{y}\cdot 1\\f_{y} =2[/tex]

The given directional derivative of f at A [tex]\vec{u}_{AD}[/tex] is

[tex]D\vec{u}_{AD}f=f_{x} \cdot \frac{3}{5} + f_{y}\cdot \frac{4}{5}[/tex]

[tex]D\vec{u}_{AD}f=9 \cdot \frac{3}{5} + 2\cdot \frac{4}{5}[/tex]

[tex]D\vec{u}_{AD}f= \frac{27+8}{5} =7[/tex]

The directional derivative of f at A in the direction of  [tex]\vec{u}_{AD}[/tex] is  7.


Related Questions

solve for " x "

[tex]x = 42 - 9[/tex]

Answers

[tex]\implies {\blue {\boxed {\boxed {\purple {\sf {x\:=\:33}}}}}}[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\red{:}}}}}[/tex]

[tex]x = 42 - 9[/tex]

➼[tex]\:x = 33[/tex]

Therefore, the value of [tex]x[/tex] is 33.

[tex]\sf\pink{Thank\:you. \:ヅ}[/tex]

Answer:

x =33

Step-by-step explanation:

x = 42-9

We are solving for x, which is already isolated

42-9 = 33

x = 33

Check 33+9 = 42

convert 4 years to months​

Answers

Answer:

48 months

Step-by-step explanation:

12 times 4 48

Answer:

48 months

There's 12 months in 1 year.

So we would multiply 12 months by 4 years to get 48 months

Sam and Mary collect marbles. “If you give me 5 marbles I’ll have twice as many as you.” said Sam to Mary.
“But if you give me 4 marbles wwe would have the same number said Mary to Sam.
How many marbles do they have altogether?

Answers

Answer:

54 marbles

Step-by-step explanation:

The question is a word problem leading to a simultaneous equation

Let 'x' represent the initial number of marbles with Sam, and let 'y' represent the initial number of marbles with Mary,

If Mary gives Sam 5 marbles, we have;

x + 5 = 2 × (y - 5)...(1)

If Sam gives Mary 4 marbles, we get;

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

From equation (1), we get;

x + 5 = 2 × (y - 5) = 2·y - 10

x = 2·y - 10 - 5 = 2·y - 15

x = 2·y - 15...(3)

From equation (2), we have;

x - 4 = y + 4

∴ x = y + 4 + 4 = y + 8

x = y + 8...(4)

Equating the two values of 'x' in equation (3), and equation (4), we get;

2·y - 15 = y + 8

2·y - y = 8 + 15 = 23

∴ y = 23

From equation (4), we get;

x = y + 8 = 23 + 8 = 31

x = 31

The total number of marbles they have altogether = x + y

However, x + y = 23 + 31 = 54

Therefore;

The total number of marbles they have altogether = 54 marbles.

2 Points

(25x

0
The equation ya

represents Michelle's regular

130(x-38) +950 %> 38

hourly and overtime wage. Based on this equation, what is Michelle's

overtime hourly pay?

A. $30

B. $38

O C. $950

O D. $25

Answers

Answer:

The answer is "35.22".

Step-by-step explanation:

Let the given equation:

[tex]\to 130(x-38) +950 \% \times 38=0\\\\\to 130x- 4940+\frac{950}{100} \times 38=0\\\\\to 130x- 4940+9.5\times 38=0\\\\\to 130x- 4940+361=0\\\\\to 130x- 4579=0\\\\\to 130x= 4579\\\\\to x= \frac{4579}{130}\\\\\to x= 35.22[/tex]

Answer: $25

Step-by-step explanation: took the quiz

if f(x)= 10 – 2x and g(x) = 6x - 5, then (f+g)(x) =

Answers

Answer:

4x +5

Step-by-step explanation:

f(x)= 10 – 2x

g(x) = 6x - 5

(f+g)(x) =10 – 2x + 6x - 5

Combine like terms

            = 4x +5

Answer:

( f + g )( x ) = 4 x + 5

Step-by-step explanation:

f ( x ) = 10 - 2 x

g ( x ) = 6 x - 5

( f + g )( x) = ( (10 - 2 x ) + (6 x -5) )

= 10 - 2x + 6 x - 5

combine like terms

= 2 x + 6 x + 10 - 5

= 4 x + 5

binomial theorem to expand (x+4)^4

Answers

Answer:

Step-by-step explanation:

(x+4)^2.(x+4)^2

= x^4 +16x^3+96x^2+256x+256

The graphs below have the same shape. What is the equation of the red
graph?
F(x) =
A. F(x) = (2 - x)
B. F(x) = (3-X)
C. F(x) = 3 - X2
D. F(x) = 2 - x?

Answers

D. F(x)=2-x^2 i know for sure because it opens downward is on the 2 of the y axis

The equation of red graph is [tex]F(x) = 2 -x^{2}[/tex].

What is the general equation of parabola?

The general equation of parabola is [tex]y = a(x-h)^{2} + k[/tex].

Where,

(h, k) are the vertices of the parabola.

According to the given question.

We have two graph.

The blue and red graph both represents the equation of downward parabola.

Since, blue graph represents the equation of downward parabola.

Whose equation is given

[tex]G(x) = 5 - x^{2}..(i)[/tex]

The general equation of a parabola is [tex]y = a(x-h)^{2} + k..(ii)[/tex]

Where, (h, k) are the vertices of the parabola.

Compare the equation (i) with (ii)

We get

(h, k) = (0, 5) and a = -1.

Now, the red graph which also represents the downward parabola whose vertices are (0, 2)

Therefore, the equation red graph is given by

[tex]F(x) = a(x-0)^{2} + 2[/tex]

⇒ [tex]F(x) = -1(x-0)^{2} + 2[/tex]

⇒ [tex]F(x) = 2 - x^{2}[/tex]

Hence, the equation of red graph is [tex]F(x) = 2 -x^{2}[/tex].

Find out more information about equation of parabola here:

https://brainly.com/question/4074088

#SPJ3

A company has the pay scales below , with the percent of employees receiving that pay listed. Find the best value to represent an average salary at this company. ( round to the nearest dollar ) Job Salary Percent of Employees Entry 23,264 60% 47,480 38% 117,027 2%

Answers

Answer:

$34,341

Step-by-step explanation:

Given :

Job Salary Percent of Employees Entry 23,264 60% 47,480 38% 117,027 2%

To obtain the best value for the mean salary ; we obtain the weighted average ;

Σ(salary * weight factor) / Σ weight

[(23264 * 0.60) + (47480 * 0.38) + (117027 * 0.02)] ÷ (0.60 + 0.38 + 0.02)

= 34341.34 / 1

Average salary = 34341.34

= $34,341 ( nearest dollar)

plsss help (on pic)
First will put brainliest

Answers

Answer:

7 over 2x-2

Step-by-step explanation:

Answer:

g^-1 •7

7g^-1

7•1/g

answer is 7/g

I hoped I helped!! :)

Helpppp and explain :)

Answers

Answer:

Problem 1: 25

Problem 2: 693

Step-by-step explanation:

Problem 1:

f(x) = -5n + 1

g(x) = -6n + 2

(f + g)(-2) = f(-2) + g(-2)

f(-2) = -5(-2) + 1

f(-2) = 10 + 1

f(-2) = 11

g(-2) = -6(-2) + 2

g(-2) = 12 + 2

g(-2) = 14

(f + g)(-2) = 11 + 14

(f + g)(-2) = 25

Problem 2:

f(x) = 7 + 2x

g(x) = 5x - 2

fg(7) = f(7) × g(7)

f(7) = 7 + 2(7)

f(7) = 7 + 14

f(7) = 21

g(x) = 5(7) - 2

g(x) = 35 - 2

g(x) = 33

Therefore:

fg(7) = 21 × 33

fg(7) = 693

what is the product of 172837286 and 17368364????

Answers

Answer:

3.0019009e+15

Step-by-step explanation:

the word and is multiplication so multiply the two numbers

Answer:

3.001900896*10^15 is the answer

Someone please help me thanks

Answers

Answer:

a. 7.2

Step-by-step explanation:

CAH (cos = adj/hyp)

cos53 = b/12; cross multiply

cos53*12 = 7.2

A would be your answer caus i’ve done it

CAN SOMEONE HELP ME OUT WITH THIS PLEASE AND THINK YOU

Answers

Answer:

[tex]10\frac{7}{18}[/tex]

Step-by-step explanation:

First revert it to improper fraction.

[tex]\frac{13}{2} +\frac{35}{9} \\\\[/tex]

Now put them to a common denominator.

[tex]\frac{187}{18}[/tex]

=> [tex]10\frac{7}{18}[/tex]

¿Cuánto mide el lado de un terreno cuadrado, si su área 144 m2?

Answers

Answer:

72

Step-by-step explanation:

all you had to do was divide by 2

The root for an equation x²-px+6=0 ls 3. Find the value of p
Jawapan / Anne
IP​

Answers

Answer:

5

Step-by-step explanation:

Given that 3 is a root of the equation x²-px+6=0

To find the value of p, substitute 3 into the equation for x

Hence x²-px+6=0

becomes

3^2 - 3p + 6 = 0

9 -3p + 6 = 0

collect like terms

-3p = -9 - 6

-3p = -15

Divide both sides by -3

p = -15/-3

p = 5

Which number(s) below belong to the solution set of the equation? Check all
that apply
x + 9 = 26
A. 17
B. 234
C. 52
D. 35
E. 26
F. 3

Answers

Answer:

A

Step-by-step explanation:

x + 9 = 26

x = 17

Answer:

A.17

Step-by-step explanation:

17+9=26

which event has exactly 12 possible outcomes?

tossing a coin 6 times

tossing a coin and randomly choosing 1 of 4 different cards

rolling a number cube with sides labeled 1 -6 and then rolling the number cube again

rolling a number cube with sides labeled 1-6 and tossing a coin


please help me TwT

Answers

Answer:

rolling a number cube with sides labeled 1-6 and tossing a coin

Step-by-step explanation:

Role dice and flip coin ;3 úwù

Please help!! Thank you if you do!!

Answers

I think it is BD but I’m not 100% sure

verify that :- 5/8x(7/9-11/6)=(5/8x7/9)-(5/8x11/6)

please answer​

Answers

The distributive law states that a(b - c) = ab - ac
In this example a = 5/8, b = 7/9 and c = 11/6

What are the values of x in the equation x2 - 6x + y =
A)x= -2 or x = 8
B)x= -1 or x = -11
C)x= 1 or x = 11
D)x = 2 or x = -8

Answers

The correct answer is A

a rule in quadratic equ states that

if summation of the roots should be -b/a of the equa

comparing the equ x² - 6x + y=0

with. ax² + bx +c =0

we see that in the equ, a= 1, b=-6

so the sum of the roots is -(-6)/1= +6

looking the the option the only one that agreed is option A

-2 + 8= 6

there fore the values of x are -2 or 8

Practice D. Factor each trinomial.
1.
x² – 2x- 8
I
2.
y2 – 13y + 42
3.
m2 - 6m - 7


Help me answer those three factor please

Answers

Answer:

So 1) x²-2x-8

= x(x-2-8/x)

2) y²-13y+42

= y(y-13+42/y)

3) m²-6m-7

= m(m-6-7/m)

Hope it helps

Consider the trapezoid shown below.
6 in.
4 in.
6 in.
6 in.
(not drawn to scale)

Answers

Answer:

36

Step-by-step explanation:

1/2bh

1/2 (6*4) =12

Considering there are three triangles we will multiply by 3

12*3=36

а
The radius
of
a circle is 10cm and
the length of a chord is 12 cm.
Then , calculate the distance between
the chord and centre of
a circle

Answers

Step-by-step explanation:

by referring to the diagram,

a = 8

a rectangle and square equal perimeter if the rectangle has width 8 cm and length 12 cm what is the area of square​

Answers

Answer:

Step-by-step explanation:

100 sq cm

CAN SOMEONE HELP ME WITH THIS PLEASE AND THANK YOU.

Answers

Answer:

six and one over twelve

Step-by-step explanation:

1/4 + 5 5/6=1/4+35/6 = 6 1/12

step 1: 5×6+5 6 step 2: 30+5 6

step 3 35

6

step 4 answer = 35

6

Find the missing side

Answers

Answer:

x=21

Step-by-step explanation:

they are corresponding to each other

pls help my computers about to die lol ​

Answers

Answer:

Elapsed 10 hours and 50 minutes

Step-by-step explanation:

So it's 5:25 pm to 4:15 am.  

It goes by 50 mins to get from 5:25 to 6:15.

Now the hours.

It has passed 10 hours to get 6:15 pm to 4;15 am.

find the value of x and y​

Answers

X=58

58-14= 44
44+58= 102
180-102= 78
78/2=39

Y=39

Answer:

x = 58

y = 39

Step-by-step explanation:

x = 58 (Vertically opposite angles)

x + 2y + (x-14) = 180 (Angles in a straight line)

=> x + 2y + x - 14 = 180

=> 2x + 2y = 180 + 14

=> 2(58) + 2y = 194

=> 116 + 2y = 194

=> 2y = 194 - 116

=> 2y = 78

=> y = 78/2

=> y = 39

Can someone help me?It's urgent and thank you!

Answers

Answer:

y = square root x2 - 5

Step-by-step explanation:

y=[tex]\sqrt{x} -5[/tex]

(the top option)

Determine if the graph is symmetric about the x-axis, the y-axis, or the origin.

r = 4 cos 5θ

Answers

Answer:

y-acis

Step-by-step explanation:

the function graph is symmetric about

- y-axis when it is an even function

-the origin ehen it is an even function

A symmetrical graph about the x-axis is not a function graph

f(×) is a even if and only if f(×) =f(×)

f(×) is a odd if and only f(×)=f(×)

We have the function r(0) = 4cos (50)

(only symmetry about the y-acis or about the origin)

Check r(-0)

r(-0) = 4cos (5-0) = 4cos (-50 = 4 cos (50)

Used cos (-× = cos ×

We have r(0). Therefore the graph of r(0) is symmectric about the y-axis.

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