<span>Length = 1200, width = 600
First, let's create an equation for the area based upon the length. Since we have a total of 2400 feet of fence and only need to fence three sides of the region, we can define the width based upon the length as:
W = (2400 - L)/2
And area is:
A = LW
Substitute the equation for width, giving:
A = LW
A = L(2400 - L)/2
And expand:
A = (2400L - L^2)/2
A = 1200L - (1/2)L^2
Now the easiest way of solving for the maximum area is to calculate the first derivative of the expression above, and solve for where it's value is 0. But since this is supposedly a high school problem, and the expression we have is a simple quadratic equation, we can solve it without using any calculus. Let's first use the quadratic formula with A=-1/2, B=1200, and C=0 and get the 2 roots which are 0 and 2400. Then we'll pick a point midway between those two which is (0 + 2400)/2 = 1200. And that should be your answer. But let's verify that by using the value (1200+e) and expand the equation to see what happens:
A = 1200L - (1/2)L^2
A = 1200(1200+e) - (1/2)(1200+e)^2
A = 1440000+1200e - (1/2)(1440000 + 2400e + e^2)
A = 1440000+1200e - (720000 + 1200e + (1/2)e^2)
A = 1440000+1200e - 720000 - 1200e - (1/2)e^2
A = 720000 - (1/2)e^2
And notice that the only e terms is -(1/2)e^2. ANY non-zero value of e will cause this term to be non-zero and negative meaning that the total area will be reduced. Therefore the value of 1200 for the length is the best possible length that will get the maximum possible area.</span>
Answer: C
Step-by-step explanation:
Subtract the total of the 3 fish she is buying from the amount of money she has:
85 - (12 + 13 + 14) = 85 - 39 = 46
She has $46 to spend on crabs.
Divide the amount she has to spend by the price on one crab:
46 / 8 = 5.75
Since it isn't a whole number you need to round down, since she cant buy 0.75 of a crab.
She has enough money to buy 5 crabs.
Answer:
The answer would be 24,590
Step-by-step explanation:
Going up the multiplication chart like so will determine the answer.
24,590 (5
19,672 (4
14,754 (3
9,836 (2
4,918 (1
Basically just try 4,918 X 5.
Answer:
A: 46 meters at 3 seconds
B: 0 meters at 6.033 seconds
C. It depends where the tree is
D. 6.033 seconds
Step-by-step explanation:
A. To find max height, we need to find the vertex.
We can do this by using vertex from y=a(x-h)+k for y=a^2+b^2+c^2
h(t) = -5t^2+30t+1
h(t)+45 = - 5x^2+30x+45+1
h(t)+45= -5(x^2-6x-9)+1
h(t)+45 = -5(x-3)^2+1
h(t) = -5(x-3)^2+46
Hence, the max height is 46 at 3 seconds
B. The minimum height is 0 meters because of the problem
C. It depends because the parabola intersects x=10 in 2 places meaning that you need the tree to be in either of these two places to intercept the horseshoe
D. -5x^2+30x+1=0
5x^2-30x-1=0
x= (30+-sqrt(30^2-4*5*-1))/2*5
x=(30+-sqrt920)/10
x=3+-2sqrt230/10
x=3+-sqrt230/5
This means that x = -0.033 or 6.033. Negative value doesn't make sense so it's 6.033 seconds
