2.
The reflector of a satellite dish is in the shape of a parabola with a diameter of 4 feet and a depth of 2 feet. To get the maximum reception we need to place the antenna at the focus.
a. Write the equation of the parabola of the cross section of the dish, placing the vertex of the parabola at the origin. Convert the equation into standard form, if necessary. What is the defining feature of the equation that tells us it is a parabola?
b. Describe the graph of the parabola. Find the vertex, directrix, and focus.
c. Use the endpoints of the latus rectum to find the focal width.
d. How far above the vertex should the receiving antenna be placed?
Answer:
Step-by-step explanation:
Assume the dish opens upwards. The cross-section through the vertex is a parabola. You know three points on the parabola: (0,0), (2,2), and (-2,2). Plug the points into y = ax² + bx + c to get a system of three equations where a=0.5, b=c=0.
Equation of parabola: y = 0.5x²
:::::
Vertex (0,0)
Focal length = 1/(4×0.5) = 0.5
Focus (0,0+0.5) = (0, 0.5)
Directrix y = 0-0.5 = -0.5
:::::
At endpoints of latus rectum, y = 0.5
x = ±√0.5 = ±√2/2
Focal width = 2×√2/2 = √2
:::::
Place antenna at focus, (9,2)
The number of dollars in x quarters
Answer:
There are four quarters in one dollar, so 4x quarters in x dollarsCircled one I need help with thank you!!
Formula-
If a set has “n” elements, then the number of subset of the given set is 2n and the number of proper subsets of the given subset is given by 2n-1. Consider an example, If set A has the elements, A = {a, b}, then the proper subset of the given subset are { }, {a}, and {b}
Symbol that can be used-
The symbol "⊆" means "is a subset of". The symbol "⊂" means "is a proper subset of".
Hope it helps you... pls mark brainliest if it helped you.
Cho hai tập hợp A={1;2;3;4},B={2;4;6;8} . Tập hợp nào sau đây bằng tập hợp A ∩B ?
Answer:
A∩B ={2;4}
Step-by-step explanation:
Chúc bạn học tốt
which polygon will NOT tessellate a plane?
Step-by-step explanation:
the answer is regular octagon
i think
Find the x- and y-intercept of the line
X+4y=36
In empty set, n (A) = ………
Answer:
answer is
In empty set, n(A) = { }.
Given that (-7,3) is on the graph of f(x), find the
corresponding point for the function
f(x) +5.
Enter the correct answer.
OOH
DONE
Clear all
?
Which points lie on the graph of f(x) = loggx?
Check all that apply.
Step-by-step explanation:
f(x)=log(x)
=d(log(x)/dx)
=>y=1/x
8-2 3/4 =
show the work
ANSWER
8-2........3/4 but you have you ADD some people dont know that 8-2= 6
and so 6/1 + 3/4 is 24/4
a coin is tossed succesively three times times . determine tje probabiliy of getting all three heads
Answer:
Answer : 1/8.
Step-by-step explanation:
Hey there!
Please see the attached picture for your answer.
Hope it helps!
Find the area of a triangle with legs that are: 12 m, 15 m, and 9 m.
Answer:
108 meters squared or m^2
Step-by-step explanation:
* means multiply
15 is probably hypotenuse because its the longest
12 and 9 are probably base and height
area = base * height
area = 12 * 9
area = 108
Answer:
54m^2
Step-by-step explanation:
Which expression is equivalent to (4x^(3)y^(5))(3x^(5)y)^(2)
Answer:
[tex](4x^3y^5)(3x^5y)^2 = 36*x^{13}y^7[/tex]
Step-by-step explanation:
Given
[tex](4x^3y^5)(3x^5y)^2[/tex]
Required
The equivalent expression
We have:
[tex](4x^3y^5)(3x^5y)^2[/tex]
Expand
[tex](4x^3y^5)(3x^5y)^2 = 4x^3y^5*9x^{10}y^2[/tex]
Further expand
[tex](4x^3y^5)(3x^5y)^2 = 4*9*x^3*x^{10}y^5*y^2[/tex]
Apply laws of indices
[tex](4x^3y^5)(3x^5y)^2 = 36*x^{13}y^7[/tex]
pls help! I need the answer quickly! thank you!
Answer:
B) 36
BA=CD
BA=9
AREA OF TRIANGLE ABC=1/2×b×h
63=1/2×b×9
126=b×9
b=14
BC=14
AD=BC
AE+ED=BC
AE=BC-ED
AE=14-6
AE=8
AREA OF TRIANGLE ACE= 1/2×AE×CD
= 1/2×8×9
=36
Find the equation of the line that contains the point (4, -2) and is perpendicular to the line y = - 2x + 5.
y = 2x - 10
y = - 2x + 6
y = - 1/2x
y = 1/2x - 4
Answer:
It's option D. y = 1/2x - 4
Step-by-step explanation:
I used Desmos to find the answer, hope the graph helps!
. A customer surveys the stock of gluten-free
breads sold in three different grocery stores.
At each grocery store, the customer counts
the number of different gluten-free breads
and compares it to the number of breads
that are not gluten-free. The table below
shows the results of this survey.
This is a relative frequency question. Applying the concept, we get that the relative frequency of gluten free breads sold at store A compared to those sold at all stores combined is 0.1667.
Relative frequency:
The relative frequency of a to b is given by a divided by b.
In this question:
a: Gluten free breads sold at store A
b: Gluten free breads sold at all stores combined.
2 + 7 + 3 = 12 gluten free breads sold.
2 sold at store A, so:
[tex]\frac{2}{12} = \frac{1}{6} = 0.1667[/tex]
Thus, the relative frequency of gluten free breads sold at store A compared to those sold at all stores combined is 0.1667.
Another example of a problem involving relative frequency you can check at https://brainly.com/question/20630951
Relative Frequency:
The relative frequency of gluten-free breads sold at Store A compared to those sold at all the stores combined is:
= 0.167
Data and Calculations:
Gluten-Free Breads at Different Stores
Gluten-Free Not Gluten-
Breads Free Breads
Store A 2 4
Store B 7 10
Store C 3 12
Since we are only considering Gluten-Free Breads at the three stores, we take the relevant data to calculate and compare their frequencies as follows:
Gluten-Free Relative
Breads Frequency
Store A 2 0.167 (2/12) = 17%
Store B 7 0.583 (7/12) = 58%
Store C 3 0.250 (3/12) = 25%
Total Gluten-free 12 1 = 100%
Thus, the relative frequency of gluten-free breads sold at Store A compared to those sold at all the stores combined is 0.167.
Based on a random sample of 50, a 95% confidence interval for the population proportion was computed. Holding everything else constant, which of the following will reduce the length of the confidence interval by half? (CHECK ALL THAT APPLY): A. Quadruple the sample size. B. Change the confidence level to 68%. C. Double the sample size. D. Change the confidence level to 99.7%. E. Decrease the sample proportion by half.
The length of the confidence interval is the margin of error, which is the ratio of the standard deviation and the square root of sample size. Hence, to reduce the length of confidence interval by half, Quadruple the sample size.
Recall :
Margin of Error = σ/√nEvaluating an hypothetical scenario :
Let standard deviation, σ = 2
Sample size = 50
Margin of Error = 2/√50 = 0.554
Using Quadruple of the sample size : (50 × 4) = 200 samples
Margin of Error = 2/√200 = 0.277(0.227 ÷ 0.554) = 0.5
Therefore, increasing the sample size, reduces the margin of error. Hence, using quadruple the sample size, will reduce the margin of error by half.
Learn more : https://brainly.com/question/13403969
Alan's aunt gave him $95 to spend on clothes at the mall. He bought 5 shirts that cost $6 each and a pair of pants that cost $17. How much money does Alan have left to buy more clothes? (one more)
Answer:
he has 48 dollars left to spend on clothes
Dylan has a coworker who is always showing up late and then not finishing his work on time. It's frustrating the other members of the team. What can he do that might help the situation? a) Complain about the coworker to other team members O b) Ask his coworker if he understands his job responsibilities c) Tell his boss that the coworker is slacking off O d) Complete his coworker's work for him
Find the number c that satisfies the conclusion of the Mean Value Theorem on the given interval. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)
f(x)= sqrt of x [0,9]
c =
Answer:
9/4
Step-by-step explanation:
f(x) is continuous and differentiable on (0,9).
We want to find c using the following equation.
f'(c)=(f(9)-f(0))/(9-0)
This will require us to find f'(x) first.
f(x)=sqrt(x) is the same as f(x)=(x)^(1/2)
Using power rule to differentiate this gives f'(x)=(1/2)(x)^(1/2-1) or simplified f'(x)=(1/2)x^(-1/2) or f'(x)=1/(2x^(1/2)).
So we want to solve:
(1/2)c^(-1/2)=(f(9)-f(0))/(9-0)
Simplify denominator on right:
(1/2)c^(-1/2)=(f(9)-f(0))/9
This will require us to find f(9) and f(0).
If f(x)=sqrt(x), then f(9)=sqrt(9)=3 and f(0)=sqrt(0)=0.
So we have the following equation so far:
(1/2)c^(-1/2)=(3-0)/9
Simplify numerator on right:
(1/2)c^(-1/2)=3/9
Multiply both sides by 2:
c^(-1/2)=6/9
Raise both sides to the -2 power:
c^(1)=(6/9)^(-2)
Note c^1=c:
c=(6/9)^(-2):
Note negative exponent means to find reciprocal of base to change exponent to opposite
c=(9/6)^2
Apply the second power:
c=81/36
Reduce by dividing top and bottom by 9:
c=9/4
This means the slope of the tangent to the curve f at x=9/4 is the same value as the slope of the secant line going through points (0,0) and (9,3).
Also 9/4 is between 0 and 9... According to the theorem we were suppose to get a value c between x=0 and x=9.
Confirmation:
Slope of the secant line is (3-0)/(9-0)=3/9=1/3.
Slope of the tangent line to curve f at x=9/4.
f'(x)=(1/2)x^(-1/2)
f'(9/4)=(1/2)(9/4)^(-1/2)
f'(9/4)=(1/2)(3/2)^(-1)
f'(9/4)=(1/2)(2/3)
f'(9/4)=1/3
They are indeed equal values (talking about the 1/3 from the secant and the tangent.)
what is the tan invers of 3i/-1-i
z = 3i / (-1 - i )
z = 3i / (-1 - i ) × (-1 + i ) / (-1 + i )
z = (3i × (-1 + i )) / ((-1)² - i ²)
z = (-3i + 3i ²) / ((-1)² - i ²)
z = (-3 - 3i ) / (1 - (-1))
z = (-3 - 3i ) / 2
Note that this number lies in the third quadrant of the complex plane, where both Re(z) and Im(z) are negative. But arctan only returns angles between -π/2 and π/2. So we have
arg(z) = arctan((-3/2)/(-3/2)) - π
arg(z) = arctan(1) - π
arg(z) = π/4 - π
arg(z) = -3π/4
where I'm taking arg(z) to have a range of -π < arg(z) ≤ π.
Need the help thanks guys
Answer:
1/4
Step-by-step explanation:
x^2 - x
Take the coefficient of x
-1
Divide by 2
-1/2
Square it
(-1/2)^2 = 1/4
Add it
x^2 -x +1/4
C 89. What is the power of 5, so that 1 its value become ? (५ को घाताङ्क 25 कति हुदा त्यसको मान 25 हुन्छ ?) .7
C 89. What is the power of 5, so that 1 its value become ?
The power is 0. because if 0 is tge powwe of any variable or letters the value becomes 1.
factor the expression completely. -30+36x
Answer:
6 (-5 + 6x)
Step-by-step explanation:
Rewrite the number 30 as 6×5 and 36 as 6×6
Factor out the common number, which is 6
so, 6 (-5 + 6x)
Answer:
-6(5-6x).
Just factor out -6 from the expression. Thank you!
The mass varies directly as the Kinetic energy (K) and inversely as the square of the velocity (V). if the kinetic energy is 80 Joules and the velocity is 4 meters per second, then the mass is 10 kilograms. Express the mass as a function of kinetic energy and velocity.
Answer:
m = [tex]\frac{2K}{v^2}[/tex]
Step-by-step explanation:
Given mass (m ) varies directly as K and inversely as v² then the equation relating them is
m = [tex]\frac{kK}{v^2}[/tex] ← k is the constant of variation
To find k use the condition m = 10 when K = 80 and v = 4 , then
10 = [tex]\frac{80k}{4^2}[/tex] = [tex]\frac{80k}{16}[/tex] ( multiply both sides by 16 to clear the fraction )
160 = 80k ( divide both sides by 80 )
2 = k
m = [tex]\frac{2K}{v^2}[/tex] ← equation of variation
The expression of mass as a function of kinetic energy and velocity is m = 2K/V².
What is an expression?Expressions are defined as mathematical statements that have a minimum of two terms containing variables or numbers.
We have been given that the mass varies directly as the Kinetic energy (K) and inversely as the square of the velocity (V).
m ∝ K/V²
m = cK/V²
Here c is the constant of variation,
If the kinetic energy is 80 Joules and the velocity is 4 meters per second, then the mass is 10 kilograms.
We have to determine the value of c
Here m = 10 , K = 80 and V = 4 , then
Substitute the values in m = cK/V²
10 = c(80)/4²
10 = c(80)/16
10 = 5c
c = 10/5
c = 2
Substitute the value of c = 2 in the equation of variation,
⇒ m = 2K/V²
Hence, the expression of mass as a function of kinetic energy and velocity is m = 2K/V².
Learn more about the expressions here:
brainly.com/question/13947055
#SPJ2
I need help ASAP please
Answer:
yes how can I help you???
Erica’s family is moving away from California. They decided to have a moving sale and sell each item for 70% off the price they originally paid for it. The sofa had an original price of $799, and the love seat had an original price of $549. What is the total cost of both items after the discount?
Find the sale price by multiplying the original price by 70% then add the two prices together to get the total.
799 x 0.70 = 559.30
549 x 0.70 = 384.30
Total: 559.30 + 384.30 = $943.60
$88 tickets to the San Francisco 49ers game are offered at a 15%
discount. What is the sale price?
Answer:
74.80
Step-by-step explanation:
First find the discount
88 * 15%
88*.15
13.2
Subtract the discount from the original price
88-13.2
74.80
translate this into an expression: the quotient of a number, x, and 8, could you please explain it to me?
Answer:
x/8
Step-by-step explanation:
First, we are given "the quotient of...". This means that we are dividing something/something else. If two numbers are given in the phrase "something and something else", the first number given will be the something, and the second number will be the something else.
The first number listed is x. Therefore, we have
x/something else.
Next, we are given "and 8", so we have x/8 as our expression
Abigail plans to repaint some classroom bookcases. She has 6/25
gallons of paint. All of the bookcases are the same size and each requires 2/3
gallon of paint. How many bookcases will the custodian be able to repaint with that amount of paint?
Answer:
Step-by-step explanation: Hello! Do
