-5 – 5 + (6 x -7) x 2

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

6. A semicircular disk of radius 3 ft. is revolved about its diameter (straight side) one complete revolution. Describe the soli

kaheart [24]

Answer:

) one complete revolution. Describe the solid determined by this revolution, and then find the volume of the solid.

Step-by-step explanation:

5 0

3 years ago

5. The Riverside Geyser in Yellowstone National Park erupts

Anastasy [175]

Answer:

Step-by-step explanation:

The equation for the model of the geyser is found by substituting the given upward velocity into the vertical motion model. The problem statement tells us v=69. We assume the height is measured from ground level, so c=0. Putting these values into the model gives ...

h(t) = -16t² +69t

__

The maximum height is at a time that is halfway between the zeros of the function.

h(t) = -16t(t -4.3125) . . . . . has zeros at t=0 and t=4.3125

The maximum height will occur at t=4.3125/2 = 2.15625 seconds. The height at that time is ...

h(t) = -16(2.15625)(2.15625 -4.3125) = 16(2.15625²) ≈ 74.39 . . . feet

The maximum height of the geyser is about 74.4 feet.

4 0

2 years ago

Example

castortr0y [4]

Answer:

6/8

Step-by-step explanation:

y^1-y^2/x^1-x^2

2+4/2+6

6/8

5 0

3 years ago

Read 2 more answers

Hi can some please help?

Oduvanchick [21]

So I'm assuming that you're taking Calculus.
The first thing you want to do is take the integral of f(x)...
Use the power rule to get:
4X^2-13X+3.
Now solve for X when f(x)=0. This is because when the slope is 0, it is either a minimum or a maximum(I'm assuming you know this)
Now you get X=0.25 and X=3. Since we are working in the interval of (1,4), we can ignore 0.25
Thus our potential X values for max and min are X=1,X=4,X=3(You don't want to forget the ends of the bounds!)
Plugging these value in for f(x), we get
f(1)=2.833
f(3)=-8.5
f(4)=1.667
Thus X=1 is the max and X=3 is the min.
So max:(1,2.833)
min:(3,-8.5)

Hope this helps!

3 0

3 years ago