The portion of the parabola y²=4ax above the x-axis, where is form 0 to h is revolved about the x-axis. Show that the surface area generated is
A=8/3π√a[(h+a)³/²-a³/2]
Use the result to find the value of h if the parabola y²=36x when revolved about the x-axis is to have surface area 1000.
Answer:
See below for Part A.
Part B)
[tex]\displaystyle h=\Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}-9\approx7.4614[/tex]
Step-by-step explanation:
Part A)
The parabola given by the equation:
[tex]y^2=4ax[/tex]
From 0 to h is revolved about the x-axis.
We can take the principal square root of both sides to acquire our function:
[tex]y=f(x)=\sqrt{4ax}[/tex]
Please refer to the attachment below for the sketch.
The area of a surface of revolution is given by:
[tex]\displaystyle S=2\pi\int_{a}^{b}r(x)\sqrt{1+\big[f^\prime(x)]^2} \,dx[/tex]
Where r(x) is the distance between f and the axis of revolution.
From the sketch, we can see that the distance between f and the AoR is simply our equation y. Hence:
[tex]r(x)=y(x)=\sqrt{4ax}[/tex]
Now, we will need to find f’(x). We know that:
[tex]f(x)=\sqrt{4ax}[/tex]
Then by the chain rule, f’(x) is:
[tex]\displaystyle f^\prime(x)=\frac{1}{2\sqrt{4ax}}\cdot4a=\frac{2a}{\sqrt{4ax}}[/tex]
For our limits of integration, we are going from 0 to h.
Hence, our integral becomes:
[tex]\displaystyle S=2\pi\int_{0}^{h}(\sqrt{4ax})\sqrt{1+\Big(\frac{2a}{\sqrt{4ax}}\Big)^2}\, dx[/tex]
Simplify:
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax}\Big(\sqrt{1+\frac{4a^2}{4ax}}\Big)\,dx[/tex]
Combine roots;
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax\Big(1+\frac{4a^2}{4ax}\Big)}\,dx[/tex]
Simplify:
[tex]\displaystyle S=2\pi\int_{0}^{h}\sqrt{4ax+4a^2}\, dx[/tex]
Integrate. We can consider using u-substitution. We will let:
[tex]u=4ax+4a^2\text{ then } du=4a\, dx[/tex]
We also need to change our limits of integration. So:
[tex]u=4a(0)+4a^2=4a^2\text{ and } \\ u=4a(h)+4a^2=4ah+4a^2[/tex]
Hence, our new integral is:
[tex]\displaystyle S=2\pi\int_{4a^2}^{4ah+4a^2}\sqrt{u}\, \Big(\frac{1}{4a}\Big)du[/tex]
Simplify and integrate:
[tex]\displaystyle S=\frac{\pi}{2a}\Big[\,\frac{2}{3}u^{\frac{3}{2}}\Big|^{4ah+4a^2}_{4a^2}\Big][/tex]
Simplify:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[\, u^\frac{3}{2}\Big|^{4ah+4a^2}_{4a^2}\Big][/tex]
FTC:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[(4ah+4a^2)^\frac{3}{2}-(4a^2)^\frac{3}{2}\Big][/tex]
Simplify each term. For the first term, we have:
[tex]\displaystyle (4ah+4a^2)^\frac{3}{2}[/tex]
We can factor out the 4a:
[tex]\displaystyle =(4a)^\frac{3}{2}(h+a)^\frac{3}{2}[/tex]
Simplify:
[tex]\displaystyle =8a^\frac{3}{2}(h+a)^\frac{3}{2}[/tex]
For the second term, we have:
[tex]\displaystyle (4a^2)^\frac{3}{2}[/tex]
Simplify:
[tex]\displaystyle =(2a)^3[/tex]
Hence:
[tex]\displaystyle =8a^3[/tex]
Thus, our equation becomes:
[tex]\displaystyle S=\frac{\pi}{3a}\Big[8a^\frac{3}{2}(h+a)^\frac{3}{2}-8a^3\Big][/tex]
We can factor out an 8a^(3/2). Hence:
[tex]\displaystyle S=\frac{\pi}{3a}(8a^\frac{3}{2})\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
Simplify:
[tex]\displaystyle S=\frac{8\pi}{3}\sqrt{a}\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
Hence, we have verified the surface area generated by the function.
Part B)
We have:
[tex]y^2=36x[/tex]
We can rewrite this as:
[tex]y^2=4(9)x[/tex]
Hence, a=9.
The surface area is 1000. So, S=1000.
Therefore, with our equation:
[tex]\displaystyle S=\frac{8\pi}{3}\sqrt{a}\Big[(h+a)^\frac{3}{2}-a^\frac{3}{2}\Big][/tex]
We can write:
[tex]\displaystyle 1000=\frac{8\pi}{3}\sqrt{9}\Big[(h+9)^\frac{3}{2}-9^\frac{3}{2}\Big][/tex]
Solve for h. Simplify:
[tex]\displaystyle 1000=8\pi\Big[(h+9)^\frac{3}{2}-27\Big][/tex]
Divide both sides by 8π:
[tex]\displaystyle \frac{125}{\pi}=(h+9)^\frac{3}{2}-27[/tex]
Isolate term:
[tex]\displaystyle \frac{125}{\pi}+27=(h+9)^\frac{3}{2}[/tex]
Raise both sides to 2/3:
[tex]\displaystyle \Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}=h+9[/tex]
Hence, the value of h is:
[tex]\displaystyle h=\Big(\frac{125}{\pi}+27\Big)^\frac{2}{3}-9\approx7.4614[/tex]
You seem to have left out that 0 ≤ x ≤ h.
From y² = 4ax, we get that the top half of the parabola (the part that lies in the first quadrant above the x-axis) is given by y = √(4ax) = 2√(ax). Then the area of the surface obtained by revolving this curve between x = 0 and x = h about the x-axis is
[tex]2\pi\displaystyle\int_0^h y(x) \sqrt{1+\left(\frac{\mathrm dy(x)}{\mathrm dx}\right)^2}\,\mathrm dx[/tex]
We have
y(x) = 2√(ax) → y'(x) = 2 • a/(2√(ax)) = √(a/x)
so the integral is
[tex]4\sqrt a\pi\displaystyle\int_0^h \sqrt x \sqrt{1+\frac ax}\,\mathrm dx[/tex]
[tex]=\displaystyle4\sqrt a\pi\int_0^h (x+a)^{\frac12}\,\mathrm dx[/tex]
[tex]=4\sqrt a\pi\left[\dfrac23(x+a)^{\frac32}\right]_0^h[/tex]
[tex]=\dfrac{8\pi\sqrt a}3\left((h+a)^{\frac32}-a^{\frac32}\right)[/tex]
Now, if y² = 36x, then a = 9. So if the area is 1000, solve for h :
[tex]1000=8\pi\left((h+9)^{\frac32}-27\right)[/tex]
[tex]\dfrac{125}\pi=(h+9)^{\frac32}-27[/tex]
[tex]\dfrac{125+27\pi}\pi=(h+9)^{\frac32}[/tex]
[tex]\left(\dfrac{125+27\pi}\pi\right)^{\frac23}=h+9[/tex]
[tex]\boxed{h=\left(\dfrac{125+27\pi}\pi\right)^{\frac23}-9}[/tex]
PlEASE HELP ILL GIVE OUT BRAINLEIST
Helppp pleaseee, abc= dce. If ac=5 and bc=7 cd=?
Answer:
CD = 5
Step-by-step explanation:
Given that ∆ACB is congruent to ∆DCE, it follows that their corresponding angles and corresponding side lengths are congruent to each other. Thus:
AC is congruent to CD,
BC is congruent to EC, and
AB is congruent to DE.
Since AC = 5, therefore CD = 5.
After the movie premiere 99 out of 130 people surveyed said they liked the movie.
What is the experimental probability that the next person surveyed will say he or she liked the movie?
What is the experimental probability that the next person surveyed will say he or she did not like the movie?
Answer:
99 over 130 multiplied by 100 over 1
Kevin and his children went into a restaurant and he bought 31.50
um kevin bought 31.50 of what? food?
multiply 4-6i and -4+2i
Answer:
-4 + 32i
Step-by-step explanation:
use the distributive property to multiply
remember: i^2 = 1
(4 - 6i)(-4 + 2i)
-16 + 8i + 24i - 12i^2
-16 + 32i - 12(- 1)
-16 + 32i +12
-4 + 32i
Answer:
4 - (6 * i)) * ((-4) + (2 * i)) =
-4 + 32 i
Step-by-step explanation:
1. Assume that men’s weights are normally distributed with a mean given by = 172lb and a standard deviation given by =29lb. Using the Central Limit Theorem to solve the following exercises(1) If 36 men are randomly selected, find the probability that they have a mean weight greater than 160lb.(2) If 81 men randomly selected, find the probability that they have a mean weight between 170lb and 175lb.
Answer:
1) 0.99348
2) 0.55668
Step-by-step explanation:
Assume that men’s weights are normally distributed with a mean given by = 172lb and a standard deviation given by =29lb. Using the Central Limit Theorem to solve the following exercises
When given a random number of samples, we use the z score formula:
z-score is z = (x-μ)/σ/√n where
x is the raw score
μ is the population mean
σ is the population standard deviation.
(1) If 36 men are randomly selected, find the probability that they have a mean weight greater than 160lb.
For x > 160 lb
z = 160 - 172/29/√36
z = 160 - 172/29/6
z = -2.48276
Probability value from Z-Table:
P(x<160) = 0.0065185
P(x>160) = 1 - P(x<160) = 0.99348
(2) If 81 men randomly selected, find the probability that they have a mean weight between 170lb and 175lb.
For x = 170 lb
z = 170 - 172/29/√81
z = 170 - 172/29/9
z = -0.62069
Probability value from Z-Table:
P(x = 170) = 0.2674
For x = 175 lb
z = 175 - 172/29/√36
z = 175- 172/29/6
z = 0.93103
Probability value from Z-Table:
P(x = 175) = 0.82408
The probability that they have a mean weight between 170lb and 175lb is calculated as:
P(x = 175) - P(x = 170)
0.82408 - 0.2674
= 0.55668
what type of transformation maps abc onto def
Answer:
The answer is translation :)
When a gas is kept at a constant temperature and pressure on it changes, its volume changes according to the following formula, known as Boyle’s law
where P1 and V1 are the pressure (in atm) and the volume (in litres) at the beginning, and P2 and V2 are the pressure and the volume at the end. Find the final pressure P2 if V1 = 1.5 litres, P1 = 4.5 atm and V2 = 3.5 litres. Round to the nearest tenth of a atm.
Answer: Approximately 1.9 atm
============================================
Work Shown:
[tex]P_1*V_1 = P_2*V_2 \ \text{ ... Boyle's Law}\\\\4.5*1.5 = P_2*3.5\\\\6.75 = P_2*3.5\\\\P_2*3.5 = 6.75\\\\P_2 = \frac{6.75}{3.5}\\\\P_2 \approx 1.92857142857142\\\\P_2 \approx 1.9\\\\[/tex]
If the volume is 3.5 liters, then the pressure is approximately 1.9 atm.
Note the increase in volume leads to the reduction of pressure, and vice versa. The two variables have an inverse relationship.
-----------
As a check,
[tex]P_1*V_1 = P_2*V_2\\\\4.5*1.5 \approx 1.9*3.5\\\\6.75 \approx 6.65\\\\[/tex]
We don't get the exact thing on both sides, but the two sides are close enough. We have rounding error due to P2 being not exact.
A more accurate check could be
[tex]P_1*V_1 = P_2*V_2\\\\4.5*1.5 \approx 1.92857*3.5\\\\6.75 \approx 6.749995\\\\[/tex]
which has the two sides much closer to one another. This helps us verify the answer.
Please help
A town has a population of 14000 and grows at 4.5% every year. To the nearest tenth of a year, how long will it be until the population will reach 41500?
Answer:
65.9
Step-by-step explanation:
Simplify each expression. (Will Give Brainlest)
Answer:
0.88
Step-by-step explanation:
-5.37 + 8.14 - 1.89
-5.37 + 6.25
= 0.88
Step-by-step explanation:
please i worked on paper worksheet
please see it
rewrite using a single positive exponent 5^6/5^4
Answer:
5²Step-by-step explanation:
We can divide exponents by subtract 4 from 6. So, now we have 5^2 or 25.
The other way to solve to check our answer is to do the math.
5^6 = 15625
5^4 = 625
15625/625 = 25
So, we know we have the correct answer.
Prove that for any natural value of n the value of the expression (n+2)^2-(n-2)^2 is a multiple of 8.
Answer:
We have the expression:
(n + 2)^2 - (n - 2)^2
Let´s break the parentheses:
(n + 2)^2 = n^2 + 4*n + 4
(n - 2)^2 = n^2 - 4n + 4
Then:
(n + 2)^2 - (n - 2)^2 = (n^2 + 4*n + 4) - (n^2 - 4n + 4) =
= (n^2 - n^2) + (4 - 4) + (4n - (-4n)) = 4n - (-4n) = 8*n
Then for any natural value of n, 8*n will be a multiple of 8.
The population of Garden City in 1995 was 2,400. In 200, the population was 4,000. Write a linear equation in slope-intercept form that represents this data.
Answer:
[tex]y = 320x +2080[/tex]
Step-by-step explanation:
Given
Population in 1995 = 2400
Population in 2000 = 4000
Required
Determine the linear equation
Let the years be represented with x.
In 1995, x = 1 i.e. the first year
In 2000, x = 6
Let y represents the population
When x = 1; y = 2400
When x = 6; y = 4000
First, we calculate the slope (m)
[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]
[tex]m = \frac{4000 - 2400}{6 - 1}[/tex]
[tex]m = \frac{1600}{5}[/tex]
[tex]m = 320[/tex]
Next, we calculate the line equation as follows:
[tex]y - y_1 = m(x - x_1)[/tex]
[tex]y - 2400 = 320(x - 1)[/tex]
[tex]y - 2400 = 320x - 320[/tex]
[tex]y = 320x - 320 + 2400[/tex]
[tex]y = 320x +2080[/tex]
Is this a function???
Answer:
pfft no lol
Step-by-step explanation:
yeah no
have a good day! :)
plz give me brainliest
Answer:
yes
Step-by-step explanation:
i think,because it goes past the center it all
If you have five red balls and five blue balls in a jar what’s the probability of the first ball being red?
Answer:
red balls = 5
blue balls = 5
total balls = 5 blue+5 red
= 10
[tex]p(first \: ball \: being \: red) = \frac{red \: balls}{total \: balls} [/tex]
[tex]p(first \: ball \: being \: red) = \frac{5}{10} = \frac{1}{2} [/tex]
Answer:
Step-by-step explanation:
Total number of red balls = 5
Total number of blue balls = 5
Total number of balls in jar = 5 + 5
= 10
Probability of the first ball being red = total number of the red ball/total number of balls in the jar
= [tex]\frac{5}{10}[/tex]
= [tex]\frac{1}{2}[/tex]
Therefore, the probability of the first ball being red = [tex]\frac{1}{2}[/tex], 50% or 0.5 (in any way you are instructed to write it in)
In which situation would it be appropriate to use square feet as a measurement?
Answer:
The correct answer is B ; Karla must determine the area of a floor in her house.
If each of two complementary angles has the same measure, then each angle will equal _____.
22.5°
90°
180°
45°
Answer:
45
Step-by-step explanation:
How do you work this problem? 10x2 +25x
Answer:
x=-5/2,0
Step-by-step explanation:
It is solved by first factorizing it
10x²+25x=5x(2x+5)=0
Finding the zeros
5x=0x=0/5=0
2x+5=0
x=-5/2
Therefore x is -5/2 or 0
y = 230x + 100
Is this proportional or non proportional?
Proportional equations are of the form y = kx, for some fixed constant k. The k value is the constant of proportionality.
The +100 at the end is why we don't have a proportional equation.
Visually all proportional equations go through the origin, meaning the lines have y intercept of 0. For y = 230x+100, the y intercept is 100.
How would I write f(x) = -4(x-2)+ 7 in standard form
Answer:
The standard form of the given equation is f(x) = 0x²-4x+15=0
Step-by-step explanation:
The standard form is ax²+bx+c=0
Given f(x) = -4(x-2)+ 7
we can write the standard form
= 0x² -4(x-2)+7 =0
⇒ 0x² -4x +8 +7 =0
⇒ 0x² -4x + 15 =0
now comparing the standard form ax²+bx+c=0
a = 0 , b= -4 and c =15
A TV report conducted a survey of 947 people in New York City and found that 35% of the population believe that the Yankees will miss the playoffs this year. In the accompanying dialogue, the reporter states, we are 97% confident that the true proportion of people in New York City who believe that the Yankees will miss the playoffs this year lies between 28% and 42% . What does 35% represent in the report
Answer:
[tex]35\%[/tex] represents the sample proportion of the population
Step-by-step explanation:
From the question we are told that
The sample size is n = 947
The proportion of the population that believes that the Yankees will miss the playoffs this year is [tex]k = 35\% = 0.35[/tex]
From the question we are told the confidence level is 97%
The lower limit of the confidence level is a = 28%
The upper limit of the b = 42%
Generally the sample proportion of this population is mathematically represented as
[tex]\^ p = \frac{a+ b}{2}[/tex]
=> [tex]\^ p = \frac{28 + 42 }{2}[/tex]
=> [tex]\^ p = 35\%[/tex]
Hence [tex]35\%[/tex] represents the sample proportion
which of the following represents the equation with a slope of 3 and a y-intercept of 2?
Answer:
c is the correct answer
Step-by-step explanation:
Please answer this is the third time I will give brainliest
Find x and y, there is no given info, and the line that is 8 units long is not a midsegment, but it is parallel to the line that is ten units long
Answer:
y = 1.75
x = 1.25
Step-by-step explanation:
Since the triangles have equal angles, you can use ratios to solve for x and y.
For y:
[tex]\frac{8}{10} =\frac{7}{a} \\8a=70\\a=8.75[/tex]
Subtract 7 from a to find y.
y = 8.75 - 7
y = 1.75
For x:
[tex]\frac{8}{10} =\frac{5}{b} \\8b=50\\b=6.25[/tex]
Subtract 5 from b to find x.
x = 6.25 - 5
x = 1.25
are any of these equations linear or nonlinear if yes what is the standard form
a. y=-7+6x
b. y=2x+5
Answer:
both are linear
a) 6x - y = 7
b) 2x - y = -5
Step-by-step explanation:
Helpppppppppppppppppppoppppppoo
Answer:
Step-by-step explanation:
abc=80, abm= 100
acb= 40, acn= 140
angle a = 60
x=80, y=40
Answer:
x = 80° y = 40°
Step-by-step explanation:
ABC = 80° ACB = 40°
ABC+ACB+A = 180° (sum of angles in a triangle = 180°)
80+40+A = 180°
A = 60° (sum of angles in a triangle = 180°)
X = 80° (ALTERNATE ANGLES, angles x is alternate to angle ABC = 80° )
y = 40° (alternate angles, angle y is alternate to angle ACB = 40°)
to cross-check : sum of angles on a straight line = 180°
x+ y + A = 180sum of angles on a straight line = 180°
80+40+60 = 180°
ABM = 100° = (sum of angles on a straight line = 180°)
80° + 100° = 180°
ACN = 140° (sum of angles on a straight line = 180°)
40° + 140° = 180°
Find the quotient for 3/2 divided by 3/5
Answer:
2.5
Step-by-step explanation:
Answer:
5/2
Step-by-step explanation:
To divide fractions, you flip the second fractions and change it to multiplication.
(3/2) / (3/5) =
(3/2) x (5/3)
To multiply them, you just multiply their numerators together to get the new numerator and multiply the denominators together to get the new denominator.
(3/2) x (5/3) =
(3 x 5) / (2 x 3) =
15/6
This can be reduced to:
5/2
Max bought a new pair of basketball shoes that were on sale for 25% off. If the regular price of the shoes was $75.95, what is the amount of discount?
Solve for y given the lines are parallel
Answer:
I believe the y is parallel :)))))))))
Answer:
35 degrees
Step-by-step explanation:
70 divided by 2 is 35.
And both sides are equal to each other bc the lines are parallel.
which statement is true regarding the functions on the graph?
Answer:
f(3)=g(3)
Step-by-step explanation:
the only one i see is that
f(3)=g(3)
because the two functions intersect there
that means the two values are the same