Which graph represents the same relation as the rule y = 2x, for all real numbers x?

Use Lagrange multipliers to find the dimensions of the box with volume 1728 cm3 that has minimal surface area. (Enter the dimens

Dima020 [189]

Answer:

(x,y,z) = (12,12,12) cm

Step-by-step explanation:

The box is assumed to be a closed box.

The surface area of a box of dimension x, y and z is given by

S = 2xy + 2xz + 2yz

We're to minimize this function subject to the constraint that

xyz = 1728

The constraint can be rewritten as

xyz - 1728 = 0

Using Lagrange multiplier, we then write the equation in Lagrange form

Lagrange function = Function - λ(constraint)

where λ = Lagrange factor, which can be a function of x, y and z

L(x,y,z) = 2xy + 2xz + 2yz - λ(xyz - 1728)

We then take the partial derivatives of the Lagrange function with respect to x, y, z and λ. Because these are turning points, each of the partial derivatives is equal to 0.

(∂L/∂x) = 2y + 2z - λyz = 0

λ = (2y + 2z)/yz = (2/z) + (2/y)

(∂L/∂y) = 2x + 2z - λxz = 0

λ = (2x + 2z)/xz = (2/z) + (2/x)

(∂L/∂z) = 2x + 2y - λxy = 0

λ = (2x + 2y)/xy = (2/y) + (2/x)

(∂L/∂λ) = xyz - 1728 = 0

We can then equate the values of λ from the first 3 partial derivatives and solve for the values of x, y and z

(2/z) + (2/y) = (2/z) + (2/x)

(2/y) = (2/x)

y = x

Also,

(2/z) + (2/x) = (2/y) + (2/x)

(2/z) = (2/y)

z = y

Hence, at the point where the box has minimal area,

x = y = z

Putting these into the constraint equation or the solution of the fourth partial derivative,

xyz - 1728 = 0

x³ = 1728

x = 12 cm

x = y = z = 12 cm.

7 0

2 years ago

Yuson used her calculator to solve the equation 4/5x - 8 = 3. She entered the following on her screen and got an incorrect answe

Firlakuza [10]

Answer:

55/4

Explanation:

Let's solve your equation step-by-step.

4 /5x−8=3

Step 1: Add 8 to both sides.

4 /5x−8+8=3+8

4 /5 x = 11

Step 2: Multiply both sides by 5/4.

( 5 /4 )*( 4 /5 x)=( 5 /4 )*(11)

x= 55/4

Answer:

x=

55 /4

Hope that helps :)

4 0

3 years ago

Read 2 more answers

A survey indicated that 3 out of 5 doctors use brand X aspirin. If 2000 doctors were surveyed, how many used brand X?

Blizzard [7]

2000(3/5)

6000/5

1200

So 1200 doctors used brand X

8 0

3 years ago

A standard deck of playing cards has 13 cards in each of four suits: hearts, clubs, diamonds, and spades. Two cards are chosen f

Aloiza [94]

Answer:

Probability of choosing one club and one spade = 0.6025

Step-by-step explanation:

Total number of cards= 52 cards

For the first event

Probability of choosing a club

Toatal club = 13 cards

Probability of choosing a club

= 13/52

Probability of choosing a club

= 1/4

Probability of choosing a club

=0.25

For the second event

Probability of choosing a spade

Toatal spade = 13 cards

Probability of choosing a spade

= 13/52

Probability of choosing spadep

= 1/4

Probability of choosing a spade = 0.25

Probability of both = 0.25*0.25

Probability of both = 0.6025

5 0

2 years ago

Stefan sells Jin a bicycle for $176 and a helmet for $16. The total cost for Jin is 160% of what Stefan spent originally to b

Elis [28]

Answer:

Stefan originally paid $120 for the bicycle and helmet.

He made $72 by selling them to Jin.

Step-by-step explanation:

Given that:

Selling price of bicycle = $176

Selling price of helmet = $16

Total price = 176+16 = $192

This is 160% of what Stefan paid originally.

Let,

x be the original amount paid by Stefan.

160% of x = 192

$\frac{160}{100}x=192\\1.6x=192$

Dividing both sides by 1.6

$\frac{1.6x}{1.6}=\frac{192}{1.6}\\x=120$

Original amount paid by Stefan = $120

Profit = 192 - 120 = $72

Hence

Stefan originally paid $120 for the bicycle and helmet.

He made $72 by selling them to Jin.

3 0

2 years ago