Answer:
[tex]r = 1.34[/tex]
Step-by-step explanation:
Given
Solid = Cylinder + 2 hemisphere
[tex]Volume = 10cm^3[/tex]
Required
Determine the radius (r) that minimizes the surface area
First, we need to determine the volume of the shape.
Volume of Cylinder (V1) is:
[tex]V_1 = \pi r^2h[/tex]
Volume of 2 hemispheres (V2) is:
[tex]V_2 = \frac{2}{3}\pi r^3 +\frac{2}{3}\pi r^3[/tex]
[tex]V_2 = \frac{4}{3}\pi r^3[/tex]
Volume of the solid is:
[tex]V = V_1 + V_2[/tex]
[tex]V = \pi r^2h + \frac{4}{3}\pi r^3[/tex]
Substitute 10 for V
[tex]10 = \pi r^2h + \frac{4}{3}\pi r^3[/tex]
Next, we make h the subject
[tex]\pi r^2h = 10 - \frac{4}{3}\pi r^3[/tex]
Solve for h
[tex]h = \frac{10}{\pi r^2} - \frac{\frac{4}{3}\pi r^3 }{\pi r^2}[/tex]
[tex]h = \frac{10}{\pi r^2} - \frac{4\pi r^3 }{3\pi r^2}[/tex]
[tex]h = \frac{10}{\pi r^2} - \frac{4r }{3}[/tex]
Next, we determine the surface area
Surface area (A1) of the cylinder:
Note that the cylinder is covered by the 2 hemisphere.
So, we only calculate the surface area of the curved surface.
i.e.
[tex]A_1 = 2\pi rh[/tex]
Surface Area (A2) of 2 hemispheres is:
[tex]A_2 = 2\pi r^2+2\pi r^2[/tex]
[tex]A_2 = 4\pi r^2[/tex]
Surface Area (A) of solid is
[tex]A = A_1 + A_2[/tex]
[tex]A = 2\pi rh + 4\pi r^2[/tex]
Substitute [tex]h = \frac{10}{\pi r^2} - \frac{4r }{3}[/tex]
[tex]A = 2\pi r(\frac{10}{\pi r^2} - \frac{4r }{3}) + 4\pi r^2[/tex]
Open bracket
[tex]A = \frac{2\pi r*10}{\pi r^2} - \frac{2\pi r*4r }{3} + 4\pi r^2[/tex]
[tex]A = \frac{2*10}{r} - \frac{2\pi r*4r }{3} + 4\pi r^2[/tex]
[tex]A = \frac{20}{r} - \frac{8\pi r^2 }{3} + 4\pi r^2[/tex]
[tex]A = \frac{20}{r} + \frac{-8\pi r^2 }{3} + 4\pi r^2[/tex]
Take LCM
[tex]A = \frac{20}{r} + \frac{-8\pi r^2 + 12\pi r^2}{3}[/tex]
[tex]A = \frac{20}{r} + \frac{4\pi r^2}{3}[/tex]
Differentiate w.r.t r
[tex]A' = -\frac{20}{r^2} + \frac{8\pi r}{3}[/tex]
Equate A' to 0
[tex]-\frac{20}{r^2} + \frac{8\pi r}{3} = 0[/tex]
Solve for r
[tex]\frac{8\pi r}{3} = \frac{20}{r^2}[/tex]
Cross Multiply
[tex]8\pi r * r^2 = 20 * 3[/tex]
[tex]8\pi r^3 = 60[/tex]
Divide both sides by [tex]8\pi[/tex]
[tex]r^3 = \frac{60}{8\pi}[/tex]
[tex]r^3 = \frac{15}{2\pi}[/tex]
Take [tex]\pi = 22/7[/tex]
[tex]r^3 = \frac{15}{2 * 22/7}[/tex]
[tex]r^3 = \frac{15}{44/7}[/tex]
[tex]r^3 = \frac{15*7}{44}[/tex]
[tex]r^3 = \frac{105}{44}[/tex]
Take cube roots of both sides
[tex]r = \sqrt[3]{\frac{105}{44}}[/tex]
[tex]r = \sqrt[3]{2.38636363636}[/tex]
[tex]r = 1.33632535155[/tex]
[tex]r = 1.34[/tex] (approximated)
Hence, the radius is 1.34cm
The radius of the cylinder that produces the minimum surface area is 1.34cm and this can be determined by using the formula area and volume of cylinder and hemisphere.
Given :
A solid is formed by adjoining two hemispheres to the ends of a right circular cylinder. The total volume of the solid is 10 cubic centimeters.The volume of a cylinder is given by:
[tex]\rm V = \pi r^2 h[/tex]
The total volume of the two hemispheres is given by:
[tex]\rm V' = 2\times \dfrac{2}{3}\pi r^3[/tex]
[tex]\rm V' = \dfrac{4}{3}\pi r^3[/tex]
Now, the total volume of the solid is given by:
[tex]\rm V_T = \pi r^2 h+\dfrac{4}{3}\pi r^3[/tex]
Now, substitute the value of the total volume in the above expression and then solve for h.
[tex]\rm 10 = \pi r^2 h+\dfrac{4}{3}\pi r^3[/tex]
[tex]\rm h = \dfrac{10}{\pi r^2}-\dfrac{4r}{3}[/tex]
Now, the surface area of the curved surface is given by:
[tex]\rm A = 2\pi r h[/tex]
Now, the surface area of the two hemispheres is given by:
[tex]\rm A'=2\times (2\pi r^2)[/tex]
[tex]\rm A'=4\pi r^2[/tex]
Now, the total area is given by:
[tex]\rm A_T = 2\pi rh+4\pi r^2[/tex]
Now, substitute the value of 'h' in the above expression.
[tex]\rm A_T = 2\pi r\left(\dfrac{10}{\pi r^2}-\dfrac{4r}{3}\right)+4\pi r^2[/tex]
Simplify the above expression.
[tex]\rm A_T = \dfrac{20}{r} + \dfrac{4\pi r^2}{3}[/tex]
Now, differentiate the total area with respect to 'r'.
[tex]\rm \dfrac{dA_T}{dr} = -\dfrac{20}{r^2} + \dfrac{8\pi r}{3}[/tex]
Now, equate the above expression to zero.
[tex]\rm 0= -\dfrac{20}{r^2} + \dfrac{8\pi r}{3}[/tex]
Simplify the above expression in order to determine the value of 'r'.
[tex]8\pi r^3=60[/tex]
r = 1.34 cm
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John puts $1,500 in a savings account that earns 7% simple interest annually. Find the new
balance in his savings account after three years if John does not deposit or withdraw any
money.
Answer:
$1,815
Step-by-step explanation:
Use the simple interest formula, I = prt
Plug in the values we know:
I = prt
I = (1,500)(0.07)(3)
I = 315
Add this to the original amount:
1500 + 315
= 1,815
So, John will have $1,815 in his account after 3 years.
1. 8x^2 + 10x - 9
2. 3x^4 - 14x^2 - 9
3. 4x^2 + 5x - 9
4. 8x^2 + 10x - 18
Answer:
4.
Step-by-step explanation:
(x^2 + 7x - 9) + (3x^2 - 2x) + (x^2 + 7x - 9) + (3x^2 - 2x)
x^2 + 7x - 9 + 3x^2 - 2x + x^2 + 7x - 9 + 3x^2 - 2x
Rearranging order:
3x^2 + 3x^2 + x^2 + x^2 + 7x + 7x - 2x - 2x - 9 - 9
Combine like terms
8x^2 + 10x - 18
What’s the equation of a line that is perpendicular to -x +2y =4 and passes through the point (-2,1)
Answer:
y = -2x - 3
Step-by-step explanation:
Given:
Equation of -x +2y =4
Point of (-2,1)
-x + 2y = 4
y = x/2 + 2 or y = 1/2x + 2
Which means the equation's slope is m = 1/2.
The slope of the perpendicular line is negative inverse which is m = -2.
Now we have an equation of y = -2x + a.
Use (-2, 1) to find a:
1 = (-2)(-2) + a
a = -3
y = - 2x - 3
Help please !!!!! Thanks
Answer:
7) y = -2
8) x = 4
Step-by-step explanation:
Any straight horizontal/vertical line you find will be x= or y=. The vertical lines are always x= because they only touch the x axis. It's the opposite for horizontal lines. For example, on number 7, the line touches -2 on the y axis. That's why it's "y=-2". Same goes for 8. the line only touches 4.
I hope this helped and wasn't confusing!
What is 3 to the 4th power
Answer:
3 to the 4th power is 81.
Step-by-step explanation:
You would do 3 × 3, which would get you to 9. Then, you multiply 9 × 9, which gives you 81.
Which of the following equations represent linear functions?
y=x2−3x
4x+y=5
y=|2x+1|
y=−5
Answer:
its y=-5x
Step-by-step explanation:
Why?
linear functions have only the slope, they dont include the y-intercept
Janice had an unpaid balance of $2358.19 on her credit card statement at the beginning of January. She made a payment of $80.00 during the month, and made purchases of $99.50. If the interest rate on Janice's credit card was 4% per month on the unpaid balance, find her finance charge and the new balance on February1.
Answer:
$2,639.19
Step-by-step explanation:
Her balance at the end of the month is
$2358.19 - $80.00 + $99.50 = $2537.69
So the finance charge is 2537.69 * 0.04% = $101.50
and her new balance is $101.50 + $2537.69 = $2639.19
The length of a rectangle is 97 meters and the width is 14 meters. Find the area. Give your answer without units.
Provide your answer below:
The area of a rectangle is the product of length and width thus the area will be 1358 square meters.
What is a rectangle?A rectangle is a geometrical figure in which opposite sides are equal.
The angle between any two consecutive sides will be 90 degrees.
The perimeter of the rectangle = 2( length + width).
It is known that,
Area of rectangle = length × width.
Area = 97 x 14 = 1358 sqare meters
Hence "The area of a rectangle is the product of length and width thus the area will be 1358 square meters".
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3. Jane Windsor financed a $5,900 ski boat with a 12% add-on interest installment loan for 12 months. Given the loan required a 10% down payment, determine the following: The amount of the finance charge? The amount of the finance charge rebate if the loan were to be paid after the 10th payment?
Answer:
multiply it by .12 then it says for 12 months, multiply it by 12 then
Step-by-step explanation:
What fraction of this shape is shaded?
You must give your answer in its simplest form.
Type here
The fraction of the shape which is shaded in simplest form is 1/3.
The square in the diagram provided has a total of 12 boxes .
The number of shaded part is 4
To calculate the shaded fraction of the shape we have to use the formula:
Number of shaded part/ Total number of boxes present.
= 4/12
We can divide the numerator and denominator by 4 to get the simplest form.
= 1/3
The fraction of the shape which is shaded in simplest form is therefore
= 1/3.
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Question 6 (1.25 points)
A researcher wants to test if the mean annual salary of all lawyers in a city is
different from $110,000. A random sample of 53 lawyers selected from the city
reveals a mean annual salary of $114,000. Assume that o = $17,000, and that the
test is to be made at the 1% significance level.
What is the value of the test statistic, z, rounded to three decimal places?
A
Answer:
Test statistic Z= 1.713
The calculated Z- value = 1.7130 < 2.576 at 0.01 level of significance
Null hypothesis is accepted
There is no difference between the mean annual salary of all lawyers in a city is different from $110,000
Step-by-step explanation:
Step(i):-
A researcher wants to test if the mean annual salary of all lawyers in a city is
different from $110,000
Mean of the Population μ = $110,000
Sample size 'n' = 53
Mean of the sample x⁻ = $114,000.
standard deviation of the Population = $17,000,
Level of significance = 0.01
Null hypothesis :
There is no difference between the mean annual salary of all lawyers in a city is different from $110,000
H₀: x⁻ = μ
Alternative Hypothesis : x⁻ ≠ μ
Step(ii):-
Test statistic
[tex]Z = \frac{x^{-}-mean }{\frac{S.D}{\sqrt{n} } }[/tex]
[tex]Z = \frac{114000-110000}{\frac{17000}{\sqrt{53} } }[/tex]
Z = 1.7130
Tabulated value Z = 2.576 at 0.01 level of significance
The calculated Z- value = 1.7130 < 2.576 at 0.01 level of significance
Null hypothesis is accepted
There is no difference between the mean annual salary of all lawyers in a city is different from $110,000
17 times the sum of a number, n, and 31 is 300. Write as an equation.
Answer:
17(n+31)=300
Step-by-step explanation:
17 times the sum of a number, n and 31 is 17(n+31)
and then set that equal to 300
You have asked to design a rectangle box with a square base and an open top. The volume of the box must be620 cm to the 3rd power. the cost of the material for the base is $0.40 per square cm and the cost of the material for the side is $0.10 per square cm.How to determine the dimension of the box that will minimize the cost of manufacturing. What is the minimum cost? in dollars and rounded to the nearest cent.
Answer:
$69.21
Step-by-step explanation:
Since the box has a square base the length and breadth of the box will be equal. Let it be [tex]x[/tex]
Let h be the height of the box
V = Volume of the box = [tex]620\ \text{cm}^3[/tex]
[tex]x^2h=620\\\Rightarrow h=\dfrac{620}{x^2}[/tex]
Now surface area of the box with an open top is given
[tex]s=x^2+4xh\\\Rightarrow s=x^2+4x\dfrac{620}{x^2}\\\Rightarrow s=x^2+\dfrac{2480}{x}[/tex]
Differentiating with respect to x we get
[tex]\dfrac{ds}{dx}=2x-\dfrac{2480}{x^2}[/tex]
Equating with zero
[tex]0=2x-\dfrac{2480}{x^2}\\\Rightarrow 2x^3-2480=0\\\Rightarrow x^3=\dfrac{2480}{2}\\\Rightarrow x=(1240)^{\dfrac{1}{3}}\\\Rightarrow x=10.74[/tex]
Double derivative of the function
[tex]\dfrac{d^2s}{ds^2}=2+\dfrac{4960}{x^3}=2+\dfrac{4960}{1240}\\\Rightarrow \dfrac{d^2s}{ds^2}=6>0[/tex]
So, x at 10.74 is the minimum value of the function.
[tex]h=\dfrac{620}{x^2}\\\Rightarrow h=\dfrac{620}{10.74^2}\\\Rightarrow h=5.37[/tex]
So, minimum length and breadth of the box is 10.74 cm while the height of the box is 5.37 cm.
The total area of the sides is [tex]4xh=4\times 10.74\times 5.37=230.7\ \text{cm}^2[/tex]
The area of the base is [tex]x^2=10.74^2=115.35\ \text{cm}^2[/tex]
Cost of the base is $0.40 per square cm
Cost of the side is $0.10 per square cm
Minimum cost would be
[tex]230.7\times 0.1+0.4\times 115.34=\$69.21[/tex]
The minimum cost of the box is 69.21 dollars.
Ezra has 21 chickens in a pen. He plans on adding 3 chickens every month to the pen. Based on this information, which representation shows this relationship between the number of chickens in the pen, y, and the number of months that have passed, x?
Answer:
Linear graph
y = 3x + 21
Step-by-step explanation:
3. Determina la solución dex en la siguiente ecuación. 10x + 3 = 9 x -2
Answer:
x=5
Step-by-step explanation:
10x + 3 = 9 x -2
10•x + 3 = 9•x -2
which is the right andwer?????????? please help me
Answer:
The first one
When the following quadratic equation is written in standard form, what is the value of "c"?
Answer:
it's 2
Step-by-step explanation:
a= -3/4
b=0
c=2
^DEF and ^RSQ are shown in the diagram below
Based on the information provided in the diagram, what is mZQ in degrees?
Answer:
53.3 degrees
Step-by-step explanation:
∆DEF and ∆RSQ are similar. We know this, because the ratio of their corresponding sides are equal. That is:
DE corresponds to RS
EF corresponds to SQ
DF corresponds to RQ.
Also <D corresponds to <R, <E corresponds to <S, and <F corresponds to <Q.
The ratio of their corresponding sides = DE/RS = 6/3 = 2
EG/SQ = 8/4 = 2
DF/RQ = 4/2 = 2.
Since the ratio of their corresponding sides are equal, it means ∆DEF and ∆RSQ are similar.
Therefore, their corresponding angles would be equal.
Thus, m<Q = m<F
Let's find angle F
m<F = 180 - (98 + 28.7)
m<F = 53.3°
Since <F corresponds to <Q, therefore,
m<Q = 53.3°
The following is a set of hypotheses, some information from one or more samples, and a standard error from a randomization distribution. Test H0 : p=0.28 vs Ha : p<0.28 when the sample has n=800, and p^=0.217 with SE=0.01.
Required:
Find the value of the standardized z-test statistic.
Answer:
Z = -6.3
Step-by-step explanation:
Given that:
[tex]\mathbf{H_o :p= 0.28}[/tex]
[tex]\mathbf{H_o :p < 0.28}[/tex]
Since the alternative hypothesis is less than 0.28, then this is a left-tailed hypothesis.
Sample sixe n = 800
[tex]\hat p[/tex] = 0.217
The standard error [tex]S.E(p) = \sqrt{\dfrac{p(1-p)}{n}}[/tex]
[tex]S.E(p) = \sqrt{\dfrac{0.28(1-0.28)}{800}}[/tex]
[tex]S.E(p) \simeq0.015[/tex]
Since this is a single proportional test, the test statistics can be computed as:
[tex]Z = \dfrac{\hat p - p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]
[tex]Z = \dfrac{0.217- 0.28}{0.01}[/tex]
Z = -6.3
The weights of broilers (commercially raised chickens) are approximately normally distributed with mean 1395 grams and standard deviation 200 grams. Use the TI-84 Plus calculator to answer the following. (a) What proportion of broilers weigh between 1160 and 1250 grams?(b) What is the probability that a randomly selected broiler weighs more than 1510 grams? (c) Is it unusual for a broiler to weigh more than 1610 grams? Round the answers to at least four decimal places.
Answer:
a) 0.0977
b) 0.3507
c) No it is not unusual for a broiler to weigh more than 1610 grams
Step-by-step explanation:
Mean = 1395 grams
Standard deviation = 200 grams. Use the TI-84 Plus calculator to answer the following.
We solve using z score formula
z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation.
(a) What proportion of broilers weigh between 1160 and 1250 grams?
For x = 1160
z = 1160 - 1395/300
= -0.78333
Probability value from Z-Table:
P(x = 1160) = 0.21672
For x = 1250 grams
z = 1250 - 1395/300
z = -0.48333
Probability value from Z-Table:
P(x = 1250) = 0.31443
The proportion of broilers weigh between 1160 and 1250 grams is
0.31443 - 0.21672
= 0.09771
≈ 0.0977
(b) What is the probability that a randomly selected broiler weighs more than 1510 grams?
For x = 1510
= z = 1510 - 1395/300
z = 0.38333
Probability value from Z-Table:
P(x<1510) = 0.64926
P(x>1510) = 1 - P(x<1510) = 0.35074
Approximately = 0.3507
(c) Is it unusual for a broiler to weigh more than 1610 grams?
For x = 1610
= z = 1610 - 1395/300
z = 0.71667
Probability value from Z-Table:
P(x<1610) = 0.76321
P(x>1610) = 1 - P(x<1610) = 0.23679
No it is not unusual for a broiler to weigh more than 1610 grams
-5x=-6
what is the value of x?
Answer: x=6/5
Step-by-step explanation:
Answer:
6/5
Step-by-step explanation:
Brian bought 20 apples. He bought twice as many as Timmy. How many apples did Timmy buy?
Answer:
10 apples
Step-by-step explanation:
if Person a bought twice as many apples as person b then it would be ten considering 10 x 2 = 20
eqaution: 10 divided by 2
if owen has a collection of nickels and quarters worth $8.10. if the nickles were quarters and the quarters were nickels, the value would be 17.70 find the number of each coin?
2
Enter the correct answer in the box.
This graph represents a transformation of the parent cube root function.
Answer: h is 5 and k is 2
Step-by-step explanation:
The equation of the transformed of the parent cube root function is
y = ∛(x-4) - 1.
How to know if a point lies in the graph of a function?All the points (and only those points) which lie on the graph of the function satisfy its equation.
Thus, if a point lies on the graph of a function, then it must also satisfy the function.
The given graph represents a transformation of the parent cube root function.
The Parent cube root function is
y = ∛(x -h) - k
where the value of h and k is equal to 0
h=0, k=0 in parent function
The graph changes direction at (0,0) in parent function.
From the given graph we can see that the graph changes direction at (4,-1) which means the graph is shifted 4 units to the right and 1 unit down
So, the value of h=4 and value of k=1
The equation of the transformed function,
y = ∛(x-4) - 1
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Solve 4X squared minus X -5 equals zero
your answer should be 1/3 if I did my math right
The mean age of several boys in a class is 12. The total is 156. How
many boys are there?
Answer:
13
Step-by-step explanation:
156/12
-9 is an example of what
Answer:
A negative number, a negative integer, a negative multiple of 3, etc.
Step-by-step explanation:
Answer:
integer
???????
Step-by-step explanation:
I'm not sure
please help me i rlly need help
Answer:
3
Step-by-step explanation:
Given a line with points; (2, 5) (3, 8).
1. Find the slope of the given line
The formula for finding the slope is:
[tex]\frac{y_{2}-y_{1} }{x_{2} - x_{1}}[/tex]
Substitute in the values;
[tex]x_{1} = 2\\y_{1} = 5\\x_{2} = 3\\y_{2} = 8[/tex]
[tex]\frac{8-5}{3-2}[/tex]
simplify;
[tex]\frac{3}{1}[/tex]
= 3
2. Find the slope of the parallel line;
Remember, when two lines are parallel, they run alongside each other, of infinitely long, but they never touch. Hence two parallel lines have the same slope. Therefore, the slope of a line that is parallel to the given one will also have the same slope as the given one, which is 3.
A large tank is partially filled with 100 gallons of fluid in which 20 pounds of salt is dissolved. Brine containing 1 2 pound of salt per gallon is pumped into the tank at a rate of 6 gal/min. The well-mixed solution is then pumped out at a slower rate of 4 gal/min. Find the number of pounds of salt in the tank after 35 minutes.
Answer:
Step-by-step explanation:
From the given information:
[tex]R_{in} = ( \dfrac{1}{2} \ lb/gal) (6)\ gal /min \\ \\R_{in} = 3 \ lb/min[/tex]
Given that the solution is pumped at a slower rate of 4gal/min
Then:
[tex]R_{out} = \dfrac{4A}{100+(6-4)t}[/tex]
[tex]R_{out}= \dfrac{2A}{50+t}[/tex]
The differential equation can be expressed as:
[tex]\dfrac{dA}{dt}+ \dfrac{2}{50+t}A = 3 \ \ \ ... (1)[/tex]
Integrating the linear differential equation; we have::
[tex]\int_c \dfrac{2}{50 +t}dt = e^{2In |50+t|[/tex]
[tex]\int_c \dfrac{2}{50 +t}dt = (50+t)^2[/tex]
multiplying above integrating factor fields; we have:
[tex](50 +t)^2 \dfrac{dA}{dt} + 2 (50 + t)A = 3 (50 +t)^2[/tex]
[tex]\dfrac{d}{dt}\bigg [ (50 +t)^2 A \bigg ] = 3 (50 +t)^2[/tex]
[tex](50 + t)^2 A = (50 + t)^3+c[/tex]
A = (50 + t) + c(50 + t)²
Using the given conditions:
A(0) = 20
⇒ 20 = 50 + c (50)⁻²
-30 = c(50) ⁻²
c = -30 × 2500
c = -75000
A = (50+t) - 75000(50 + t)⁻²
The no. of pounds of salt in the tank after 35 minutes is:
A(35) = (50 + 35) - 75000(50 + 35)⁻²
A(35) = 85 - [tex]\dfrac{75000}{7225}[/tex]
A(35) =69.6193 pounds
A(35) [tex]\simeq[/tex] 70 pounds
Thus; the number of pounds of salt in the tank after 35 minutes is 70 pounds.
There are 4 trucks for every 5 cars in a parking lot. If there are 80 cars, how many trucks are in the parking lot?
Answer:
There are 64 trucks!
Step-by-step explanation: