<span>Maximum area = sqrt(3)/8
Let's first express the width of the triangle as a function of it's height.
If you draw an equilateral triangle, then a rectangle using one of the triangles edges as the base, you'll see that there's 4 regions created. They are the rectangle, a smaller equilateral triangle above the rectangle, and 2 right triangles with one leg being the height of the rectangle and the other 2 angles being 30 and 60 degrees. Let's call the short leg of that triangle b. And that makes the width of the rectangle equal to 1 minus twice b. So we have
w = 1 - 2b
b = h/sqrt(3)
So
w = 1 - 2*h/sqrt(3)
The area of the rectangle is
A = hw
A = h(1 - 2*h/sqrt(3))
A = h*1 - h*2*h/sqrt(3)
A = h - 2h^2/sqrt(3)
We now have a quadratic equation where A = -2/sqrt(3), b = 1, and c=0.
We can solve the problem by using a bit of calculus and calculating the first derivative, then solving for 0. But since this is a simple quadratic, we could also take advantage that a parabola is symmetrical and that the maximum value will be the midpoint between it's roots. So let's use the quadratic formula and solve it that way. The 2 roots are 0, and 1.5/sqrt(3).
The midpoint is
(0 + 1.5/sqrt(3))/2 = 1.5/sqrt(3) / 2 = 0.75/sqrt(3)
So the desired height is 0.75/sqrt(3).
Now let's calculate the width:
w = 1 - 2*h/sqrt(3)
w = 1 - 2* 0.75/sqrt(3) /sqrt(3)
w = 1 - 2* 0.75/3
w = 1 - 1.5/3
w = 1 - 0.5
w = 0.5
The area is
A = hw
A = 0.75/sqrt(3) * 0.5
A = 0.375/sqrt(3)
Now as I said earlier, we could use the first derivative. Let's do that as well and see what happens.
A = h - 2h^2/sqrt(3)
A' = 1h^0 - 4h/sqrt(3)
A' = 1 - 4h/sqrt(3)
Now solve for 0.
A' = 1 - 4h/sqrt(3)
0 = 1 - 4h/sqrt(3)
4h/sqrt(3) = 1
4h = sqrt(3)
h = sqrt(3)/4
w = 1 - 2*(sqrt(3)/4)/sqrt(3)
w = 1 - 2/4
w = 1 -1/2
w = 1/2
A = wh
A = 1/2 * sqrt(3)/4
A = sqrt(3)/8
And the other method got us 0.375/sqrt(3). Are they the same? Let's see.
0.375/sqrt(3)
Multiply top and bottom by sqrt(3)
0.375*sqrt(3)/3
Multiply top and bottom by 8
3*sqrt(3)/24
Divide top and bottom by 3
sqrt(3)/8
Yep, they're the same.
And since sqrt(3)/8 looks so much nicer than 0.375/sqrt(3), let's use that as the answer.</span>
Answer:
they are perpendicular
Step-by-step explanation:
because the slope are opposite which means the lines intersect.
Answer:
2.72 inches
Step-by-step explanation:
1.4/1.12 = 1.25
3.4/1.25 = 2.72
Answer:
(-4,0) and (4,0)
Step-by-step explanation:
The x-intercepts occur for values of x where f(x) = 0.
f(x) = 0 when the nominator (
) = 0.
is a difference of squares,
so you can factor it as (x + 4)(x – 4)
When x = –4 or x = 4, the nominator is 0, and f(x) = 0
Answer:
C 20
Step-by-step explanation:
Set up equations:
Laguna's Truck Rentals
y = 2x + 20
Where x is the number of miles driven and y is the total price
<em>How did we get to this equation?</em>
Well, the company charges $2 for every mile driven. Therefore, by multiplying 2 and x, you will find the price paid per mile. The 20 (which represents $20) is the one-time payment you pay for simply using the service.
Salvatori's Truck Rentals
y = 3x
Where x is the number of miles driven and y is the total price
<em>How did we get to this equation?</em>
For this company, you only pay for how many miles you drive. There isn't a one-time payment like there is for Laguna's Truck Rentals. Therefore, you only need to multiply the price per mile ($3) by the number of miles driven (x).
Set the equations equal to each other:
2x + 20 = 3x
<em>Why would you do this?</em>
We need to set the equations equal to each other because we need to find the point at which the prices are the same. When two things are the same, they are equal. Therefore, we get rid of the y variable (which represents the total price) because we want to find the value of x when the equations are equal to one another.
Solve:
2x + 20 = 3x
Subtract 2x on both sides:
2x + 20 = 3x
-2x -2x
20 = x
When x is equal to 20, or when the number of miles driven is 20, the total price of the Truck Rental services is the same.
Hope this helps :)
