What’s the answer of this problem

A landscape architect wished to enclose a rectangular garden on one side by a brick wall costing $20/ft and on the other three s

makvit [3.9K]

Answer:

The dimensions of the garden that minimize the cost is 9.018 feet(length) and 13.528 feet(width)

Step-by-step explanation:

Let the length of garden be x

Let the breadth of garden be y

Area of Rectangular garden = $Length \times Breadth = xy$

We are given that the area of the garden is 122 square feet

So, $xy=122$ ---A

A landscape architect wished to enclose a rectangular garden on one side by a brick wall costing $20/ft

So, cost of brick along length x = 20 x

On the other three sides by a metal fence costing $10/ft.

So, Other three side s = x+2y

So, cost of brick along the other three sides= 10(x+2y)

So, Total cost = 20x+10(x+2y)=20x+10x+20y=30x+20y

Total cost = 30x+20y

Substitute the value of y from A

Total cost = $30x+20(\frac{122}{x})$

Total cost = $\frac{2440}{x}+30x$

Now take the derivative to minimize the cost

$f(x)=\frac{2440}{x}+30x$

$f'(x)=-\frac{2440}{x^2}+30$

Equate it equal to 0

$0=-\frac{2440}{x^2}+30$

$\frac{2440}{x^2}=30$

$\sqrt{\frac{2440}{30}}=x$

$9.018 =x$

Now check whether it is minimum or not

take second derivative

$f'(x)=-\frac{2440}{x^2}+30$

$f''(x)=-(-2)\frac{2440}{x^3}$

Substitute the value of x

$f''(x)=-(-2)\frac{2440}{(9.018)^3}$

$f''(x)=6.6540$

Since it is positive ,So the x is minimum

Now find y

Substitute the value of x in A

$(9.018)y=122$

$y=\frac{122}{9.018}$

$y=13.528$

Hence the dimensions of the garden that minimize the cost is 9.018 feet(length) and 13.528 feet(width)

4 0

3 years ago

Describe the locus in space.

yanalaym [24]

Answer: an endless cylinder with radius 4 mm and centerline

8 0

3 years ago

Y = (x) = (1/16)^x<br> Find f(x) when x = (1/4)

Naddik [55]

Answer:

1/2

Step-by-step explanation:

(1/16)^x

Let x = 1/4

(1/16)^ 1/4

Rewriting 16 as 2^4

(1/2^4)^ 1/4

We know that 1 / a^b = a^-b

(2 ^ -4)^ 1/4

We know that a^b^c = a^(b*c)

2^(-4*1/4)

2^-1

We know that a^-b = 1/ a^b

2^-1 = 1/2^1 = 1/2

7 0

3 years ago

Read 2 more answers

Complete the equation of the line through ( 4 , -8 ) and ( 8 , 5 )

irinina [24]

Answer:

Therefore the equation of the line through ( 4 , -8 ) and ( 8 , 5 ) is

13x - 4y = 84.

Step-by-step explanation:

Given:

Let,

point A( x₁ , y₁) ≡ ( 4 ,-8)

point B( x₂ , y₂) ≡ (8 , 5)

To Find:

Equation of Line AB =?

Solution:

Equation of a line passing through Two points A( x₁ , y₁) and B( x₂ , y₂)is given by the formula

$(y - y_{1} )=(\frac{y_{2}-y_{1} }{x_{2}-x_{1} })\times(x-x_{1}) \\$

Substituting the given values in a above equation we get

$(y-(-8))=(\frac{5-(8)}{8-4})\times (x-4)\\ \\(y+8)=\frac{13}{4}(x-4)\\\\4(y+8)=13(x-4)\\4y+32=13x-52\\13x-4y=84...............\textrm{which is the required equation of the line AB}$

Therefore the equation of the line through ( 4 , -8 ) and ( 8 , 5 ) is

13x - 4y = 84.

4 0

3 years ago

Help, Solve for y 7=35y

Lapatulllka [165]

Answer:

0.2 = y

Step-by-step explanation: You have to isolate y

35 35

0.2 = y

RECHECK:

7 = 35y

7 = 35(0.2)

7 = 7

YES, this is a true statement.

Hope this helps you!!! :)

4 0

3 years ago