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2 years ago

Calculate the gradient of BD

Mathematics

1 answer:

den301095 [7]2 years ago

7 0

Step-by-step explanation:

part 1 : explaining how to get the coordinates of B

part 2 : the gradient of BD

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A cylinder shaped can needs to be constructed to hold 500 cubic centimeters of soup. The material for the sides of the can costs

iogann1982 [59]

Answer:

r=3.628cm

h=12.093cm

Step-by-step explanation:

For this problem we are going to use principles, concepts and calculations from multivariable calculus; mainly we are going to use the Lagrange multipliers method. This method is thought to help us to find a extreme value of a multivariable function 'F' given a restriction 'G'. F represents the function that we want to optimize and G is just a relation between the variables of which F depends. The Lagrange method for just one restriction is:

$\nabla F=\lambda \nabla G$

First, let's build the function that we want to optimize, that is the cost. The cost is a function that must sum the cost of the sides material and the cost of the top and bottom material. The cost of the sides material is the unitary cost (0.03) multiplied by the sides area, which is $A_s=2\pi rh$ for a cylinder; while the cost of the top and bottom material is the unitary cost (0.05) multiplied by the area of this faces, which is $A_{TyB}=2\pi r^2$ for a cylinder.

So, the cost function 'C' is:

$C=2\pi rh*0.03+2\pi r^2*0.05\\C=0.06\pi rh+0.1\pi r^2$

The restriction is the volume, which has to be of 500 cubic centimeters:

$V=500=\pi r^2h\\500=\pi hr^2$

So, let's apply the Lagrange multiplier method:

$\nabla C=\lambda \nabla V\\\frac{\partial C}{\partial r}=0.06\pi h+0.2\pi r\\\frac{\partial C}{\partial h}=0.06\pi r\\\frac{\partial V}{\partial r}=2\pi rh\\\frac{\partial V}{\partial h}=\pi r^2\\(0.06\pi h+0.2\pi r,0.06\pi r)=\lambda (2\pi rh,\pi r^2)$

At this point we have a three variable (h,r, λ)-three equation system, which solution will be the optimum point for the cost (the minimum). Let's write the system:

$0.06\pi h+0.2\pi r=2\lambda \pi rh\\0.06\pi r=\lambda \pi r^2\\500=\pi hr^2$

(In this kind of problems always the additional equation is the restricion, in this case, V=500).

Let's divide the first and second equations by π:

$0.06h+0.2r=2\lambda rh\\0.06r=\lambda r^2\\500=\pi hr^2$

Isolate λ from the second equation:

$\lambda =\frac{0.06}{r}$

Isolate h from the third equation:

$h=\frac{500}{\pi r^2}$

And then, replace λ and h in the first equation:

$0.06*\frac{500}{\pi r^2} +0.2r=2*(\frac{0.06}{r})r\frac{500}{\pi r^2} \\\frac{30}{\pi r^2}+0.2r= \frac{60}{\pi r^2}$

Multiply all the resultant equation by $\pi r^{2}$ :

$30+0.2\pi r^3=60\\0.2\pi r^3=30\\r^3=\frac{30}{0.2\pi } =\frac{150}{\pi}\\r=\sqrt[3]{\frac{150}{\pi}}\approx 3.628cm$

Then, find h by the equation $h=\frac{500}{\pi r^2}$ founded above:

$h=\frac{500}{\pi r^2}\\h=\frac{500}{\pi (3.628)^2}=12.093cm$

4 0

3 years ago

Find the equation of the straight line passing through the point (3,5) which is perpendicular to the line y=3x+2

ohaa [14]

Answer:

y=-1/3x+6 .Hope this helps

5 0

3 years ago

Read 2 more answers

Partial quotient for 654 divided by 3

Vladimir79 [104]

654 over 3 = divide the both 654 and 3 by 3.

It will give you 218 over 1.

So the answer is 218.

6 0

2 years ago

Jason has 1/6 yard of wire . He cuts it into 4 pieces of same length.what is the length in yards of each piece.

klemol [59]

Answer:

1/24 yards.

Step-by-step explanation:

1/6 / 4

= 1/6 * 1/4

= 1/24.

7 0

3 years ago

Kiera is in her last year of college at the University of Houston. She has a scholarship that pays 75% of her costs. Her classes

sergiy2304 [10]

If the scholarship pays 75% of her classes cost, that means that she has to pay the 25% remaining of the classes cost so if we calculate it as follow:

0.25 * $14,000 = $3,500
=================================================================
Another method to understand:
if the scolarship pays 75% of her classes that will be
0.75* $14,000 = $10,500

now she has to pay the remaining of the total cost and that will be
$14,000 - $10,500 = $3,500.

5 0

3 years ago

Calculate the gradient of BD​

Calculate the gradient of BD