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3 years ago

Help !!! ..............

Mathematics

1 answer:

arlik [135]3 years ago

7 0

The second one is the answer, apply distance formula you get the distance between (-2,0) and (1,sqrt(7)) is 4, means the point lies on the circle

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A school wishes to enclose its rectangular playground using 480 meters of fencing.

Harlamova29_29 [7]

Answer:

Part a) $A(x)=(-x^2+240x)\ m^2$

Part b) The side length x that give the maximum area is 120 meters

Part c) The maximum area is 14,400 square meters

Step-by-step explanation:

The picture of the question in the attached figure

Part a) Find a function that gives the area A(x) of the playground (in square meters) in terms of x

we know that

The perimeter of the rectangular playground is given by

$P=2(L+W)$

we have

$P=480\ m\\L=x\ m$

substitute

$480=2(x+W)$

solve for W

$240=x+W\\W=(240-x)\ m$

<u><em>Find the area of the rectangular playground</em></u>

The area is given by

$A=LW$

we have

$L=x\ m\\W=(240-x)\ m$

substitute

$A=x(240-x)\\A=-x^2+240x$

Convert to function notation

$A(x)=(-x^2+240x)\ m^2$

Part b) What side length x gives the maximum area that the playground can have?

we have

$A(x)=-x^2+240x$

This function represent a vertical parabola open downward (the leading coefficient is negative)

The vertex represent a maximum

The x-coordinate of the vertex represent the length that give the maximum area that the playground can have

Convert the quadratic equation into vertex form

$A(x)=-x^2+240x$

Factor -1

$A(x)=-(x^2-240x)$

Complete the square

$A(x)=-(x^2-240x+120^2)+120^2$

$A(x)=-(x^2-240x+14,400)+14,400$

$A(x)=-(x-120)^2+14,400$

The vertex is the point (120,14,400)

therefore

The side length x that give the maximum area is 120 meters

Part c) What is the maximum area that the playground can have?

we know that

The y-coordinate of the vertex represent the maximum area

The vertex is the point (120,14,400) -----> see part b)

therefore

The maximum area is 14,400 square meters

Verify

$x=120\ m$

$W=(240-120)=120\ m$

The playground is a square

$A=120^2=14,400\ m^2$

8 0

3 years ago

Can somebody please help?

kari74 [83]

Step-by-step explanation:

√121 - √-192 - √4 + √-48

= 11 - 192i - 2 + 48i

= 9 - 144i

= 9(1 - 16i).

6 0

3 years ago

A projectile is fired into the air with an initial vertical velocity of 160 ft/sec from ground level. How many seconds later doe

djverab [1.8K]

The maximum height of the projectile is the maximum point that can be gotten from the projectile equation

The projectile reaches the maximum height after 5 seconds

The function is given as:

$\mathbf{h(t) = -16t^2 + 160t}$

Differentiate the function with respect to t

$\mathbf{h'(t) = -32t + 160}$

Set to 0

$\mathbf{h'(t) = -32t + 160 = 0}$

So, we have:

$\mathbf{-32t + 160 = 0}$

Collect like terms

$\mathbf{-32t =- 160 + 0}$

$\mathbf{-32t =- 160}$

Solve for t

$\mathbf{t = \frac{- 160}{-32}}$

$\mathbf{t = 5}$

Hence, the projectile reaches the maximum after 5 seconds