Answer:
(-3,-3)
B=(6-9,6+3)
32. Identify all real and non-real zeros of the function f(x) = x^3 + 5x^2 + 3x + 15.
options:
A. x = 0, −5, 1.7i, −1.7i
B. x = 0,−5, 1.7i
C. x = −5, 1.7i, −1.7i
D. x = 0,−3, −5
Answer:
x = -5 or x = i sqrt(3) or x = -i sqrt(3)
Step-by-step explanation:
Solve for x:
x^3 + 5 x^2 + 3 x + 15 = 0
The left hand side factors into a product with two terms:
(x + 5) (x^2 + 3) = 0
Split into two equations:
x + 5 = 0 or x^2 + 3 = 0
Subtract 5 from both sides:
x = -5 or x^2 + 3 = 0
x = (0 ± sqrt(0^2 - 4×3))/2 = ( ± sqrt(-12))/2:
x = -5 or x = sqrt(-12)/2 or x = (-sqrt(-12))/2
sqrt(-12) = sqrt(-1) sqrt(12) = i sqrt(12):
x = -5 or x = (i sqrt(12))/2 or x = (-i sqrt(12))/2
sqrt(12) = sqrt(4×3) = sqrt(2^2×3) = 2sqrt(3):
x = -5 or x = (i×2 sqrt(3))/2 or x = (-i×2 sqrt(3))/2
(2 i sqrt(3))/2 = i sqrt(3):
x = -5 or x = i sqrt(3) or x = (-2 i sqrt(3))/2
(2 (-i sqrt(3)))/2 = -i sqrt(3):
Answer: x = -5 or x = i sqrt(3) or x = -i sqrt(3)
Answer:
C. x = −5, 1.7i, −1.7i
Step-by-step explanation:
Quick answer:
C. x = −5, 1.7i, −1.7i
explanation:
C. is the only answer option that does NOT have 0 as a root, which is impossible, because there is a constant term, which means that all roots are non-zero. In other words, we cannot extract x as a factor.
Complete answer:
All odd degree polynomials have at least one real root.
By the real roots theorem, we know that
if there is a real root, it must be of the form [tex]\pm[/tex]p/q where q is any of the factors of the leading coefficient (1 in this case) and p is any factor of the constant term d (15 in this case).
Values of [tex]\pm[/tex]p/q are
On trial and error, using the factor theorem, we see that
f(-5) = 0, therefore -5 is a real root. By long division, we have a quotient of x^2+3 = 0, which gives readily the remaining (complex) roots of +/- sqrt(5) i
The answer is {-5, +/- sqrt(5) i}, or again,
C. x = −5, 1.7i, −1.7i
Y varies inversely with x. If Y=17 and k(The constant of variation) =76, what is x? Round to the nearest tenth if necessary.
Answer:
x ≈ 4.5
Step-by-step explanation:
Given y varies inversely with x then the equation relating them is
y = [tex]\frac{k}{x}[/tex] ← k is the constant of variation
Here k = 76 and y = 17 , thus
17 = [tex]\frac{76}{x}[/tex] ( multiply both sides by x )
17x = 76 ( divide both sides by 17 )
x ≈ 4.5 ( to the nearest tenth )
A random sample of 1003 adult Americans was asked, "Do you pretty much think televisions are a necessity or a luxury you could do without?" Of the 1003 adults surveyed, 521 indicated that televisions are a luxury they could do without.
Requried:
a. Obtain a point estimate for the population proportion of adult Americans who believe that televisions are a luxury they could do without.
b. Verify that the requirements for constructing a confidence interval about p are satisfied.
c. Construct and interpret a 95% confidence interval for the population proportion of adult Americans who believe that televisions are a luxury they could do without.
d. Is it possible that a supermajority (more than 60%) of adult Americans believe that television is a luxury they could do without ? Is it likely?
e. Use the results of part (c) to construct a 95% confidence interval for the population proportion of adult Americans who believe that televisions are a necessity.
Answer:
a)0.519
b)requirements for constructing a confidence interval about p are satisfied.
c)0.488, and 0.550
d)yes this is because there is no possibility
that the true proportion is not captured in the confidence interval.
e)
0.450, 0.512
Step-by-step explanation:
a)The point estimate for the population proportion of adult Americans who believe that televisions are a luxury they could do without can be calculated as
521 of that adult that indicated that televisions are a luxury they could do without/1003 adults surveyed,
p = 521/1003
= 0.519.
b)
np(1-p)=1003×(0.519)×(1-0.519)
=250.39≥10 and the sample size is less than 5% of the population
therefore, requirements for constructing a confidence interval about p are satisfied.
c) we were given 95% confidence,
Then α=(1-0.95)
= 0.05
From the Z-tables,we can get the critical value is Z , which is (0.05/2) = Z (0.025) = 1.96
confidence interval can the be calculated using the formula below
- p ± Z*√ p (1 – p)/n
=0.519 ± 1.96√0.519×(1 – 0.519)/(1003)
= 0.519 ± 1.96×0.0158
0.519 ± 0.031
= 0.488, and 0.550
d) yes this is because there is no possibility
that the true proportion is not captured in the confidence interval.
e)the sample size can be calculated as
P=x/n
=(1003-521)/1003
=0.481
But we're given 95% confidence interval
Then
α=(1-0.95)=
0.05
From the Z-tables,we can get the critical value is Z , which is (0.05/2) = Z (0.025) = 1.96
Then convidence interval=
- p ± Z*√ p (1 – p)/n
=0.481 ± 1.96√0.481×(1 – 0.481)/(1003)
0.450, 0.512
A leaf blower was marked up 100% from an original cost of $152. If Eva bought the leaf blower and paid 7% sales tax, how much in total did she pay?
Answer:
$325.28
Step-by-step explanation:
152+152=304
304x1.07=325.28
Answer:
325.28
Step-by-step explanation:
increase the price by 100 %
152* 100%
152
Add this to the original price
152+152 = 304
Now find the sales tax
304 * 7%
304 * .07
21.28
Add this to the amount of the purchase price
304+21.28
325.28
The equation of a circle centered at the origin with a radius of unit length is x2 + y2 = 1. This equation changes if the center of the circle is not located at the origin or the radius is not of unit length.
Answer:
The equation for a unit radius circle, centered at the origin is:
x^2 + y^2 = 1
Now, if we want to move it horizontally, you can recall to the horizontal translations:
f(x) -----> f(x - a)
Moves the graph to the right by "a" units.
A vertical translation is similar.
Then, if we want a circle centered in the point (a, b) we have:
(x - a)^2 + (y - b)^2 = 1.
Now, if you want to change the radius, we can actually write the unit circle as:
x^2 + y^2 = 1^2
Where if we set x = 0, 1 = y, this is our radius
So if we have:
x^2 + y^2 = R^2
And we set the value of x = 0, then R = y.
So our radius is R.
Then:
"A circle of radius R, centered in the point (a, b) is written as:
(x - a)^2 + (y - b)^2 = R^2
Assume that a random sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level.
Answer:
Margin of Error = z∝/2 * Standard Error
Step-by-step explanation:
The formula for standard error is given by
SE = [tex]\sqrt{\frac{pq}{n} }[/tex]
Where p is the probability or proportion of success q=1-p and n is the number of trials or samples.
Now Margin of Error is given by
ME = z∝/2 * Standard Error
The confidence level is used to estimate the value of alpha.
For example 90% confidence means alpha= 1-0.9= 0.1 and alpha by 2 would be 0.05 . So the value for alpha by 2 would be 1.96
A hunter shot 7 ducks. The hunter's dog recovered 5/7 of the ducks. How many ducks were recover
Answer:
5
Step-by-step explanation:
Just multiply 5/7 by 7 since his dog retrieved 5/7 out of the 7 ducks he shot.
Answer:
5
Step-by-step explanation:
7*5/7
7 represents the # of ducks
5/7 represents the # of ducks that were recovered
The question asks the number of ducks that were recovered so you should multiply the total # of ducks there are by the fraction that were recovered.
Which of the following points IS a solution to the system: y > - 3x + 4 / y > 2x / - y < 7 Selected answer is not correct.
Answer:
Solution : Third Option
Step-by-step explanation:
The first step here is to make all the signs uniform. As you can see the third inequality has a less than sign, which we can change to a greater than sign by dividing negative one on either side, making the inequality y > - 7.
[tex]\begin{bmatrix}y>-3x+4\\ y>2x\\ y>-7\end{bmatrix}[/tex]
Now take a look at the third option. Of course the y - coordinate, 3, is greater than - 7, so it meets the third requirement ( y > - 7 ). At the same time 3 > 1( 2 ) > 2, and hence it meets the second requirement as well. 3 > - 3( 1 ) + 4 > - 3 + 4 > 1, meeting the first requirement.
Therefore, the third option is a solution to the system.
State the correct polar coordinate for the graph shown:
Answer:
Solution : ( - 5, 5π / 4 )
Step-by-step explanation:
There are four cases to consider here, the first two with respect to r > 0, the second two with respect to r < 0. r is the directed distance from the pole, and theta is the directed angle from the positive x - axis. Let's start by listing coordinates when r is positive. r here is 5 units from the positive x - axis.
( 5, θ ) theta here is between 30 and 60 degrees, so we can say it's about 45 degrees.
( 5, θ ) theta here is the remaining negative side of 360 - 45 = 315. That would make it - 315.
And when r is negative ( r < 0 ),
( - 5, θ ) now the point is going to lie on the ray pointing in the opposite direction of the terminal side of theta. This will be 45 degrees more than 180, or 180 + 45 = 225 degrees.
Right away we know that ( - 5, 225° ) is our solution, we don't have to consider the second case. Converting 225 to radians in terms of π will be 5π / 4 radians, giving us a solution of ( - 5, 5π / 4 ) or option b.
Write 4–6 sentences explaining why it is important to have precise definitions in mathematics.
If Q(x)=x2−6x−2, find Q(−4).
Answer:
Q(-4) = 38Step-by-step explanation:
Q(x)=x² − 6x − 2
To find Q(−4) substitute the value of x which is - 4 into Q(x)
That's
Q(-4) = (-4)² - 6(-4) - 2
Q(-4) = 16 + 24 - 2
We have the final answer as
Q(-4) = 38Hope this helps you
x + y + z = -6 -2x – 2y – 2z = 12 5x + 5y + 5z = -30 find x y and z please
Answer:
x = s, y = t, z = -6 -s -t
Step-by-step explanation:
These are dependent equations. For some values s and t, the solution is ...
x = s, y = t, z = -6 -s -t
Suppose we want to test the color distribution claim on the M&M’s website that a bag of plain M&M’s is made up of 10% blue, 10% orange, 10% green, 20% red, 20% yellow, and 30% brown. We select a sample of 400 plain M&M’s and found the following: Color Blue Orange Green Red Yellow Brown Frequency 30 48 55 66 70 131
Is there evidence to doubt the color distribution claimed by the website? Use =0.05
Answer:
Calculated χ² = 13.425
χ² (5,0.025) >14.45 and χ²(5,0.975) <1.24
The given data does not fall in the critical region so we accept H0 and conclude there is no evidence to doubt the color distribution claimed by the website.
Step-by-step explanation:
Color Blue Orange Green Red Yellow Brown
Frequency 30 48 55 66 70 131
Expected 40 40 40 80 80 120
H0: The bag of plain M&Ms is made up of 10% blue, 10% orange, 10% green, 20% red, 20% yellow, and 30% brown
Ha: The color distribution is not equal to the distribution stated in the null hypothesis.
Calculate chi square
χ² = (30-40)² /40 + (48-40)²/40 + (55-40)²/40 + (66-80)²/80 + (70-80)²/80 + (131-120)²/120
χ² = 2.5 + 1.6 + 5.625 + 2.45 + 1.25= 13.425
The critical region for χ² for 5 degrees of freedom with ∝= 0.05 is
χ² (5,0.025) >14.45 and χ²(5,0.975) <1.24
The given data does not fall in the critical region so we accept H0 and conclude there is no evidence to doubt the color distribution claimed by the website.
Answer the questions attached about the given sequence: -33, -27, -21, -15, ...
Answer:
see below
Step-by-step explanation:
-33, -27, -21, -15,....
-33 +6 = -27
-27+6 = -21
-21+6 = -15
This is an arithmetic sequence
The common difference is +6
explicit formula
an=a1+(n-1)d where n is the term number and d is the common difference
an = -33 + ( n-1) 6
an = -33 +6n -6
an = -39+6n
recursive formula
an+1 = an +6
10th term
n =10
a10 = -39+6*10
= -39+60
=21
sum formula
see image
The sum will diverge since we are adding infinite numbers
Use the gradient to find the directional derivative of the function at P in the direction of Q. g(x, y, z) = xye^z, P(2, 4, 0), Q(0, 0, 0)
Answer: Find answer in the attached files
Step-by-step explanation:
Make Q the subject of the formula A = Q2 - 2a.
Answer:
[tex]\huge\boxed{Q = \sqrt{A+2a}}[/tex]
Step-by-step explanation:
[tex]A = Q^2 -2a[/tex]
Adding 2a to both sides
[tex]Q^2 = A+2a[/tex]
Taking sqrt on both sides
[tex]Q = \sqrt{A+2a}[/tex]
Avi's pet hamster Chubby loves to run in his hamster wheel. During one "race", Avi counts 100100100 rotations of the wheel. She wants to know how far Chubby ran, so she measures the diameter of the wheel and finds that it is 20 \text{ cm}20 cm20, start text, space, c, m, end text. How far did Chubby run? Round your answer to the nearest \text{cm}cmstart text, c, m, end text.
Answer:
63 cm
Step-by-step explanation:
If Chubby ran his wheel, which has a diameter of 20cm, we want to find its circumference - this will tell us how far Chubby has ran one one full rotation of the wheel.
The formula for the circumference of a circle is [tex]2\pi r[/tex], where r is the radius. We know the diameter is 20, which is double the radius, so the radius is [tex]20\div2=10[/tex] cm.
We can know substitute inside the formula:
[tex]2\cdot \pi \cdot10\\\\2\cdot 3.14 \cdot10\\\\ 6.28\cdot10\\\\62.8[/tex]
62.8 rounded to the nearest cm is 63.
Hope this helped!
Answer:
6280
Step-by-step explanation:
what is 76.32 divided by 24.98 using compatible numbers to estimate each quotient?
Answer:
Approximately 3.05
Step-by-step explanation:
Using "compatible numbers" we can simply round these numbers to integer values. Let's make 76.32 => 76 and 24.98 => 25
So from here let's do 76/25 to get 3 R 1/25
1/25 as a decimal is .04
So far, we have 3.04. Going back to Look at our decimals, .32 and .98, there is a larger difference in our down rounding with the .32 than the up rounding from our .98. So we should consider an extra value in our decimal.
Considering our whole number of 3.0, we can assume that our rounding will have an increase of about .01 or .015 in error.
Thus our number will be 3.04 + .01.
Making our quotient approximately 3.05.
Cheers.
Find the value of x , 5x =625 , also find 3x and 2x-1
Answer:
That's your answer
x= 125
3x= 375
2x-1= 249
You are to manufacture a rectangular box with 3 dimensions x, y and z, and volume v=8000. Find the dimensions which minimize the surface area of this box.
Answer:
20 by 20 by 20
Step-by-step explanation:
Let the total surface of the rectangular box be expressed as S = 2xy + 2yz + 2xz
x is the length of the box
y is the width and
z is the height of the box.
S = 2xy + 2yz + 2xz ... 1
Given the volume V = xyz = 8000 ... 2
From equation 2;
z = 8000/xy
Substituting into equation 1;
S = 2xy + 2y(8000/xy)+ 2x(8000/xy)
S = 2xy+16000/x+16000/y
Differentiating the resulting equation with respect to x and y will give;
dS/dx = 2y + (-16000x⁻²)
dS/dx = 2y - 16000/x²
Similarly,
dS/dy = 2x + (-160000y⁻²)
dS/dy = 2x - 16000/y²
Note that at the turning point, ds/dx = 0 and ds/dy = 0, hence;
2y - 16000/x² = 0 and 2x - 16000/y² = 0
2y = 16000/x² and 2x = 16000/y²
2y = 16000/(8000/y²)²
2y = 16000×y⁴/64,000,000
2y = y⁴/4000
y³ = 8000
y =³√8000
y = 20
Given 2x = 16000/y²
2x = 16000/20²
2x = 16000/400
2x = 40
x = 20
Since Volume of the box is V = xyz
8000 = 20(20)z
8000 = 400z
z = 8000/400
z = 20
Hence, the dimensions which minimize the surface area of this box is 20 by 20 by 20.
The dimensions which minimize the surface area of this box is 20 *20* 20. This can be calculated by using surface area and volumes.
The calculation for total surface area:Let the total surface of the rectangular box be expressed as:
S = 2xy + 2yz + 2xz
where,
x is the length of the box
y is the width and
z is the height of the box.
S = 2xy + 2yz + 2xz .................(1)
Given:
Volume V = xyz = 8000 .............(2)
From equation 2;
z = 8000/xy
Substituting into equation 1;
S = 2xy + 2y(8000/xy)+ 2x(8000/xy)
S = 2xy+16000/x+16000/y
Differentiating the resulting equation with respect to x and y will give;
dS/dx = 2y + (-16000x⁻²)
dS/dx = 2y - 16000/x²
Similarly,
dS/dy = 2x + (-160000y⁻²)
dS/dy = 2x - 16000/y²
Note that at the turning point, ds/dx = 0 and ds/dy = 0, hence;
2y - 16000/x² = 0 and 2x - 16000/y² = 0
2y = 16000/x² and 2x = 16000/y²
2y = 16000/(8000/y²)²
2y = 16000×y⁴/64,000,000
2y = y⁴/4000
y³ = 8000
y =³√8000
y = 20
Given 2x = 16000/y²
2x = 16000/20²
2x = 16000/400
2x = 40
x = 20
Since, Volume of the box is V = xyz
8000 = 20(20)z
8000 = 400z
z = 8000/400
z = 20
Hence, the dimensions which minimize the surface area of this box is 20*20*20.
Find more information about Surface area here:
brainly.com/question/1090412
please answer! I need these points for grade!
∡NMO = 59°
Step-by-step explanation:if MO bisect =>
=> ∡LMN = 2∡LMO =>
=> 5x - 22 = 2(x + 31)
5x - 22 = 2x + 62
5x - 2x = 62 + 22
3x = 84
x = 28°
∡LMO = ∡NMO => ∡NMO = x + 31
=> ∡NMO = 28 + 31 = 59°
wo independent samples have been selected, 100 observations from population 1 and 76 observations from population 2. The sample means have been calculated to be x⎯⎯⎯1=11.9 and x⎯⎯⎯2=12.9. From previous experience with these populations, it is known that the variances are σ21=27 and σ22=23. (a) Determine the rejection region for the test of
Answer:
[tex]\text{Critical Region} = z<-1.96\ \text{or}\ z>1.96[/tex]
Step-by-step explanation:
A test for the difference between two population means is to be performed.
As the population variances are known, the z-test will be used.
The hypothesis can be defined as follows:
H₀: μ₁ = μ₂ vs. Hₐ: μ₁ ≠ μ₂
Assume that the significance level of the test is, α = 0.05.
The critical region can be defined as follows:
The critical value of z for α = 0.05 is:
[tex]z_{\alpha/2}=z_{0.05/2}=z_{0.025} =-1.96\\\\z_{1-\alpha/2}=z_{1-0.05/2}=z_{0.975} =1.96[/tex]
Use a z-table.
[tex]\text{Critical Region} = z<-1.96\ \text{or}\ z>1.96[/tex]
|5x|=3 please help me
Which of the following best defines the midpoint of a segment? A. The point that splits a line segment into two equal parts. B. Any point on a line segment in between the two endpoints. C. When a line segment is split into equal thirds, a midpoint is any point in the middle third. D. Any point that is closer to one endpoint of the segment than the other.
Answer:
A. The point that splits a line segment into two equal parts.
Step-by-step explanation:
A. The point that splits a line segment into two equal parts.
Midpoint, as the word suggests, means the point which lies in the middle of something. The correct option is A.
What does a midpoint mean?Midpoint, as the word suggests, means the point which lies in the middle of something. The midpoint of a line segment means a point which lies in the mid of the given line segment.
The statement that best describes the midpoint of a segment is the point that splits a line segment into two equal parts.
Learn more about Midpoint:
https://brainly.com/question/5127660
#SPJ5
a function includes the points (4, -3) and (-9,4). what fraction in lowest terms represents the output value of this function for an input of zero
Answer:
-11/13
Step-by-step explanation:
The equation of the line through these points can be written using the 2-point form of the equation of a line:
y = (y2 -y1)/(x2 -x1)(x -x1) +y1
y = (4 -(-3))/(-9-4)/(x -4) -3
y = (-7/13)x +28/13 -3
For x=0, the value of y is ...
y = 28/13 -39/13 = -11/13
The output for an input of 0 is -11/13.
PLEASE HELP ! (2/5) -50 POINTS -
Answer:
symmetric
Step-by-step explanation:
it kind of evenly falls to the left and right from the highest value in the middle
skewed would be different and would look like a straight line not a quadratic equation
Jay is copying an angle. His work so far is shown below. Explain the importance of his next step, which is placing the point of the compass on L, opening the compass to N, and drawing an arc.
A. This ensures that when he draws another arc for angle Y, that it will be the right distance from point Z. <-- MY ANSWER
B. This arc is to make sure that both L and N are equidistant from M.
C. This arc makes sure that the distance from L to N is the same as the distance from Y to Z.
D. This way there will be two arcs drawn on both angles when he is done.
Answer:
your answer is correct.
Step-by-step explanation:
For the purpose here, we'll call the missing point on the arc through Z point X.
Essentially, you want to make ΔXYZ ≅ ΔLMN by SSS. The construction so far ensures LM ≅ MN ≅ XY ≅ YZ. By copying the length LN to XZ, you ensure the congruence of the remaining sides of the triangles.
Then ∠XYZ ≅ ∠LMN because corresponding parts of congruent triangles are congruent.
In short, XZ needs to be the same distance as LN.
A box of chocolates contains five milk chocolates, three dark chocolates, and four white chocolates. You randomly select and eat three chocolates. The first piece is milk
chocolate, the second is white chocolate, and the third is milk chocolate. Find the probability of this occuring.
Answer:
60/220
Step-by-step explanation:
we use combination,
[tex] (\frac{5}{1} ) \times ( \frac{4}{1} ) \times ( \frac{3}{1} )[/tex]
[tex]5 \times 4 \times 3 = 60[/tex]
then, all divided by,
[tex] (\frac{12}{3}) = 220 [/tex]
[tex]60 \div 220[/tex]
The probability of the first piece being milk chocolate, the second being white chocolate, and the third being milk chocolate is 0.06.
What is Probability?The probability helps us to know the chances of an event occurring.
[tex]\rm Probability=\dfrac{Desired\ Outcomes}{Total\ Number\ of\ outcomes\ possible}[/tex]
The sample contains five milk chocolates, three dark chocolates, and four white chocolates. Therefore, the probability that the first piece is milk chocolate is
[tex]\rm Probability=\dfrac{\text{Number of Milk choclates}}{\text{Total number of choclates}}[/tex]
[tex]\rm Probability=\dfrac{5}{12}[/tex]
Now, since the chocolate is been eaten the sample size will reduce from 12 chocolates in total to 11 chocolates in total (four milk chocolates, three dark chocolates, and four white chocolates). Therefore, the probability of the second piece being white chocolate is
[tex]\rm Probability=\dfrac{\text{Number of White choclates}}{\text{Total number of choclates}}[/tex]
[tex]\rm Probability=\dfrac{4}{11}[/tex]
Now, as the chocolate is been eaten the sample size will reduce from 11 chocolates in total to 10 chocolates in total (four milk chocolates, three dark chocolates, and three white chocolates). Therefore, the probability of the third piece being milk chocolate is
[tex]\rm Probability=\dfrac{\text{Number of Milk choclates}}{\text{Total number of choclates}}[/tex]
[tex]\rm Probability=\dfrac{4}{10}[/tex]
Thus, the probability of the first piece being milk chocolate, the second being white chocolate, and the third being milk chocolate is
[tex]\rm Probability=\dfrac{5}{12}\times \dfrac{4}{11} \times \dfrac{4}{10} = \dfrac{80}{1320} = 0.06[/tex]
Hence, the probability of the first piece being milk chocolate, the second being white chocolate, and the third being milk chocolate is 0.06.
Learn more about Probability:
https://brainly.com/question/795909
Apple introduced the first iPod in October 2001. Sales of the portable music player grew slowly in the early years but began to grow rapidly after 2005. But the iPod era is coming to a close. Smartphones with music and video
Apple introduced the first iPod in October 2001. Sales of the portable music player grew slowly in the
END OF THE IPOD ERA
players are replacing the iPod, along with the category of device it helped to create. Sales of the iPod worldwide from 2007
through 2011 (in millions) were
approximately
N(0= -165t2 + 13.13t+ 39.9 (0 < t< 4)
in year t, where t= 0 corresponds to 2007. Show that the worldwide sales of the iPod peaked sometime in 2009. What was the approximate largest number of iPods sold worldwide from 2007 through 2011?
Answer:
a. t = 2.48 will be a period within 2009.
b. 56.16 million
Step-by-step explanation:
Here is the complete question
Apple introduced the first iPod in October 2001. Sales of the portable music player grew slowly in the early years but began to grow rapidly after 2005. But the iPod era is coming to a close. Smartphones with music and video
Apple introduced the first iPod in October 2001. Sales of the portable music player grew slowly in the
END OF THE IPOD ERA
players are replacing the iPod, along with the category of device it helped to create. Sales of the iPod worldwide from 2007
through 2011 (in millions) were
approximately
N(0= -2.65t2 + 13.13t+ 39.9 (0 < t< 4)
in year t, where t= 0 corresponds to 2007. Show that the worldwide sales of the iPod peaked sometime in 2009. What was the approximate largest number of iPods sold worldwide from 2007 through 2011?
a. Show that the worldwide sales of the iPod peaked sometime in 2009
N(t) = -2.65t² + 13.13t + 39.9
To find the maximum value of N(t), we find dN(t)/dt and equate it to zero
dN(t)/dt = d[-2.65t² + 13.13t + 39.9]/dt
dN(t)/dt = -5.3t + 13.13 = 0
-5.3t = - 13.13
t = -13.13/(-5.3)
t = 2.477
t ≅ 2.48
d²N(t)/dt² =d[-5.3t + 13.13]/dt = -5.3 < 0. So, t = 2.48 is a maximum point
Since t = 2 is 2009 and t = 3 is 2010, t = 2.48 will be a period within 2009.
b. What was the approximate largest number of iPods sold worldwide from 2007 through 2011?
The approximate largest number of ipods sold is when t = 2.48
N(2.48) = -2.65(2.48)² + 13.13(2.48) + 39.9
N(2.48) = -16.29856 + 32.5624 + 39.9
N(2.48) = 56.16384
N(2.48) ≅ 56.16 million
Find the sum of the first 12 terms of the sequence 512, 256, 128, …
Answer: 1023.75 (a)
Step-by-step explanation:
The sequence is a Geometric progression with the common ratio of ¹/₂ and first term of 512.
a = 512, r = ¹/₂. To determine the ratio, just divide the second term by the first term.
Now to calculate the sum, we consider two formula here and select the one that is most appropriate,
(1) a( rⁿ - 1 )/r - 1, when r is greater than 1
(2) a( 1 - rⁿ )/1 - rⁿ, when r is less than 1.
In this question, formula 2 shall be appropriate because r is less than 1.
so,
S₁₂ = 512( 1 - 0.5¹² )/1 - 0.5
512( 1 - 2.44 ₓ 10⁻⁴ )/0.5
= 512( 0,9998 )/0.5
= 511.875/0.5
= 1023.75
The answer is a
