Step-by-step explanation:
ccxiddidificifificici i i ivi i i i i i i i iivvii iix9difi
Write the sum using summation notation, assuming the suggested pattern continues.
100 + 121 + 144 + 169 + ... + n2 + ...
100 = 10², so the sum you're considering is the sum of squared integers starting with 10.
[tex]\displaystyle 100+121+144+168+\cdots+n^2+\cdots = \boxed{\sum_{k=10}^\infty k^2}[/tex]
A study was conducted in order to estimate ?, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be ? = 3.6 hours.
A similar study conducted a year earlier estimated that ?, the mean number of weekly hours that U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance level of 5%) whether the current study provides significant evidence that this mean has changed since the previous year.
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
a. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
b. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
c. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
d. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
e. None of the above. The only way to reach a conclusion is by finding the p-value of the test.
Answer:
d. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
Step-by-step explanation:
Mean was of 8 hours, test if it has changed:
At the null hypothesis, we test if it has not changed, that is, the mean is still of 8, so:
[tex]H_0: \mu = 8[/tex]
At the alternative hypothesis, we test if it has changed, that is, the mean is different of 8, so:
[tex]H_1: \mu \neq 8[/tex]
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
8 is part of the confidence interval, which means that the study does not provide evidence that the mean has changed, and the correct answer is given by option d.
if f(x)=x+7 and 9(x)=1/x-13 what is the domain of (f•g)(x)
Answer:
The only limitation is x≠0
The interval notation is (-∞,0)∪(0,∞)
Step-by-step explanation:
Set up the expression.
[tex](x+7)*(\frac{1}{x}-13)[/tex]
Multiply using FOIL.
[tex](x*\frac{1}{x})+(x*-13)+(7*\frac{1}{x})+(7*-13)[/tex]
[tex]1-13x+\frac{7}{x}-91[/tex]
[tex]-13x+\frac{7}{x}-91[/tex]
Find the Domain.
The only limitation is x≠0
The interval notation is (-∞,0)∪(0,∞)
Help please and thank you!!!!!
9514 1404 393
Answer:
a) 2 and 4; b) 1&2, 2&3, 3&4x = 16Step-by-step explanation:
1a. Vertical angles share a vertex and are composed of opposite rays. Here, angles 2 and 4 are vertical angles.
1b. Consecutively numbered angles are adjacent, as are angles 1 and 5. The pairs of interest can be chosen from ...
1&2, 2&3, 3&4, 4&5, 5&1
__
2. Angles 1 and 3 have the same measure, because they are vertical angles. Then we have ...
78° = (5x -2)°
80 = 5x . . . . . . . divide by °, add 2
16 = x . . . . . . . divide by 5
Decompose -6x/(x+2)(x+8) into partial fractions.
The partial fraction expansion takes the form
-6x/((x + 2) (x + 8)) = a/(x + 2) + b/(x + 8)
Both factors in the denominator are linear, so the numerators in the corresponding partial fractions have degree 1 - 1 = 0 and are thus constants.
Combine the fractions on the right side into one with a common denominator, then set the numerators on both sides of the equation equal to each other:
-6x = a (x + 8) + b (x + 2)
Expand the right side and collect terms by powers of x :
-6x = (a + b) x + (8a + 2b)
It follows that
a + b = -6 and 8a + 2b = 0
==> a = -2 and b = 8
So we end up with
-6x/((x + 2) (x + 8)) = -2/(x + 2) + 8/(x + 8)
Maria reads 3/5 chapters in 5/6 hours whats the unit rate?
Answer: 18/25 chapters / hour
Step-by-step explanation:
Concept:
Here, we need to know the idea of unit rate.
A unit rate is a rate with 1 in the denominator.
In simple words, the unit rate is something per one thing. For example, when you go to a store, you bought a book that is priced at $10. In actually meaning, it is $10 per book, or $10/book.
Solve:
Given formula
Unit rate = Number of chapters / Hours
Substitute the value into the formula
Unit rate = (3/5) / (5/6)
Convert to multiplication by taking the reciprocal of the divisor
Unit rate = (3/5) · (6/5)
Numerator times numerator / denominator times denominator
Unit rate = (3 × 6) / (5 × 5)
Unit rate = 18 / 25 chapter / hour
Hope this helps!! :)
Please let me know if you have any questions
The unit rate is 18/25 chapters per hour. This means Maria is reading at a rate of 18/25 chapters in one hour.
How to determine the unit rateTo calculate the unit rate, we're trying to find out how much of something (in this case, chapters) happens in a single unit of another thing (time, in hours).
In this scenario, Maria reads 3 out of 5 chapters in 5 out of 6 hours. To find the unit rate, we divide the chapters read (3/5) by the time taken (5/6 hours):
Unit Rate = Chapters Read / Time Taken
= (3/5) / (5/6)
To divide fractions, we multiply the first fraction by the reciprocal of the second fraction:
Unit Rate = (3/5) * (6/5)
= (3 * 6) / (5 * 5)
= 18 / 25
So, the unit rate is 18/25 chapters per hour. This means Maria is reading at a rate of 18/25 chapters in one hour.
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If a normally distributed population has a mean (mu) that equals 100 with a standard deviation (sigma) of 18, what will be the computed z-score with a sample mean (x-bar) of 106 from a sample size of 9?
Answer:
Z = 1
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Mean (mu) that equals 100 with a standard deviation (sigma) of 18
[tex]\mu = 100, \sigma = 18[/tex]
Sample of 9:
This means that [tex]n = 9, s = \frac{18}{\sqrt{9}} = 6[/tex]
What will be the computed z-score with a sample mean (x-bar) of 106?
This is Z when X = 106. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{106 - 100}{6}[/tex]
[tex]Z = 1[/tex]
So Z = 1 is the answer.
b) An achievement test was administered to a class of 20,000 students. The mean score was 80 and the standard deviation was 11. If Lingard scored 72 in the test, how many students did better than him
Answer: 15328
Step-by-step explanation:
The following can be deduced from the information given:
N = 20000
μ = 80
σ = 11
P(X>72) = 1 - P (X<72)
= 1 - P(Z < 72-80/11)
= 1 - P(Z < -8/11)
= 1 - P(Z < 0.7272)
= 1 - 0.2336 = 0.7664
Therefore, the number of students that were better than Lingard n(X > 72) will be:
= 20000 × 0.7664
= 15328
What is the solution of log3x + 4 4096 = 4?
Step-by-step explanation:
X= - 1
X=0
X=4/3
X=3
We solve for x by simplifying both sides of the equation, then isolate the variable.
Answer :
C (x=4/3)
Verify the given linear approximation at a = 0. Then determine the values of x for which the linear approximation is accurate to within 0.1. (Enter your answer using interval notation. Round your answers to three decimal places.) 1/((1 + 9x)^4) ≈ 1 − 36x
Answer:
Part 1)
See Below.
Part 2)
[tex]\displaystyle (-0.179, -0.178) \cup (-0.010, 0.012)[/tex]
Step-by-step explanation:
Part 1)
The linear approximation L for a function f at the point x = a is given by:
[tex]\displaystyle L \approx f'(a)(x-a) + f(a)[/tex]
We want to verify that the expression:
[tex]1-36x[/tex]
Is the linear approximation for the function:
[tex]\displaystyle f(x) = \frac{1}{(1+9x)^4}[/tex]
At x = 0.
So, find f'(x). We can use the chain rule:
[tex]\displaystyle f'(x) = -4(1+9x)^{-4-1}\cdot (9)[/tex]
Simplify. Hence:
[tex]\displaystyle f'(x) = -\frac{36}{(1+9x)^{5}}[/tex]
Then the slope of the linear approximation at x = 0 will be:
[tex]\displaystyle f'(1) = -\frac{36}{(1+9(0))^5} = -36[/tex]
And the value of the function at x = 0 is:
[tex]\displaystyle f(0) = \frac{1}{(1+9(0))^4} = 1[/tex]
Thus, the linear approximation will be:
[tex]\displaystyle L = (-36)(x-(0)) + 1 = 1 - 36x[/tex]
Hence verified.
Part B)
We want to determine the values of x for which the linear approximation L is accurate to within 0.1.
In other words:
[tex]\displaystyle \left| f(x) - L(x) \right | \leq 0.1[/tex]
By definition:
[tex]\displaystyle -0.1\leq f(x) - L(x) \leq 0.1[/tex]
Therefore:
[tex]\displaystyle -0.1 \leq \left(\frac{1}{(1+9x)^4} \right) - (1-36x) \leq 0.1[/tex]
We can solve this by using a graphing calculator. Please refer to the graph shown below.
We can see that the inequality is true (i.e. the graph is between y = 0.1 and y = -0.1) for x values between -0.179 and -0.178 as well as -0.010 and 0.012.
In interval notation:
[tex]\displaystyle (-0.179, -0.178) \cup (-0.010, 0.012)[/tex]
A study was done to determine the proportion of voters that feel that their local government is doing an adequate job. Of the 220 voters surveyed, 175 feel that their local government is doing an adequate job. Calculate the 95% confidence interval for the true proportion of voters that feel that their government is doing an adequate job.
Answer:
( 0.742, 0.849 )
Step-by-step explanation:
sample size = 220
number of voters with positive response ( i.e. number of voters who believe the government is doing right ) = 175
Calculate the 95% confidence interval
P = 175 / 220 = 0.796
the 95% confidence interval = ( 0.796 ± 0.054 )
attached below is the detailed solution
Michael is 4 times as old as Brandon and is also 27 years older than Brandon.
How old is Brandon?
Answer:
9
Step-by-step explanation:
b = Brandon
4b=b+27
-b -b
-------------
3b = 27
---- ----
3 3
b = 9
Brandon is 9 years old.
In the parallelogram below, solve for x.
D (9x + 5)
E
G
F (13 - 43y
Answer:
[tex]x = 12[/tex]
Step-by-step explanation:
Given
[tex]\angle D = 9x + 5[/tex]
[tex]\angle F = 13x -43[/tex]
Required
Find x
To find x, we make use of:
[tex]\angle D =\angle F[/tex] --- opposite angles of a parallelogram
So, we have:
[tex]9x + 5 =13x -43[/tex]
Collect like terms
[tex]9x - 13x = -5-43[/tex]
[tex]-4x = -48[/tex]
Divide by -4
[tex]x = 12[/tex]
Hey guys can help me please
Answer:
Can you select multiple answers to this question? then option A, B and C all three applies, if only one the go for option C, since that's the major change happens to the parent function
write 342 to 1 significant figure
Answer:
300
Step-by-step explanation:
A significant figure is the most important (largest) number you can round it to.
As it wants 1 significant figure, you count 1 to the left and round the 4 down.
Hope this helps :)
To almirahs are purchased for 7,800.
200 was spent on the transportation. One of them is sold at a profit of 40% and the other one at a loss of 40% If the selling price was same in both the cases, and the cost price of each almirah
Answer:
The Cost Price of the Almirah Is 4000
Which facts are true for the graph of the function below? Check all that apply.
F(x)-(3/7)^x
Answer:
Step-by-step explanation:
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
PLEASE HELP URGENT!!!
Janine determines that the total resistance in her circuit is 80 ohms. Using the inverse equation modeling this situation, find the resistance of the second lightbulb.
The resistance of the second lightbulb is ohms.
A. 120
B. 240
C. 300
D. 40
The sum of resistors arranged in parallel is the inverse of the sum of the inverses of the magnitudes of the individual resistances
The correct option for the resistance of the second light bulb in ohms (Ω) is option B;
B. 240
The reason why option B is the correct answer is s follows:
Known parameters:
Based on a online search, the question appears to have some parts missing which can be as follows;
The resistance of the first light bulb = 120 Ω
Janine's model of the total resistance of the circuit, [tex]t = \mathbf {\dfrac{120 \cdot r }{r + 120} }[/tex]
Where;
r = The resistance of the second light bulb
The unknown parameter:
Resistance of the second light bulb
Method:
Find r using Janine's model of the total resistance, which is the equation of total resistances in parallel arrangement
The inverse relationship modelling the sum, t, of resistances, r, and 120, arranged in parallel, presented as follows;
[tex]\mathbf {\dfrac{1}{t} } =\dfrac{1}{120} + \dfrac{1}{r}[/tex]
∴ [tex]\mathbf {\dfrac{1}{t}} = \dfrac{r + 120 }{120 \cdot r}[/tex]
Therefore, by finding the inverse of both sides of the above equation, we get Janine's model as follows;
[tex]t = \mathbf {\dfrac{120 \cdot r }{r + 120} }[/tex]
The above equation is the inverse equation modelling the total resistance of the parallel arrangement of the resistances in the lightbulb
The question details include:
The total resistance in her circuit, t = 80 Ω
Solution:
Plugging in t = 80 in [tex]t = \mathbf {\dfrac{120 \cdot r }{r + 120} }[/tex], gives;
[tex]80 = \mathbf {\dfrac{120 \cdot r }{r + 120} }[/tex]
Therefore, we get;
80·(r + 120) = 120·r
80·r + 80 × 120 = 120·r
∴ 120·r - 80·r = 80 × 120 = 9,600
120·r - 80·r = 40·r
∴ 40·r = 9,600
r = 9,600/40 = 240
The resistance of the second light bulb, r = 240 Ω
Learn more about series and parallel circuits here;
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https://brainly.com/question/20446619
Answer:240
Step-by-step explanation:
i watched the walk through
Help me please and thank you
Answer:
Option C is correct
Step-by-step explanation:
[tex]log( {10}^{3} )[/tex]
Use logarithm rules to move 3 out of the exponent.[tex]3 \: log \: (10)[/tex]
Logarithm base 10 of 10 is 1.[tex]3×1[/tex]
Multiply 3 by 1.[tex]3[/tex]
Hope it is helpful....A gardener makes a new circular flower bed. The bed is ten feet in diameter.Calculate the circumference and the area of the circular flower bed
Answer:
It will be 31.4 cm rounded off for circumference
It will be 78.53 cm2 rounded off for area
Step-by-step explanation:
Diameter = 10 cm
Radius = 10/2 cm = 5 cm
Circumference = 2×pi×radius
= 2pi×5
= 31.4 cm
Area = pi × r square
= 25 pi
= 78.53cm2
Fill in the blank with a number to make the expression a perfect square.
u^2- 18u +
Answer:
u^2- 18u +81 = (u-9)^2
Step-by-step explanation:
u^2- 18u +
Take the u coefficient
-18
Divide by 2
-18/2 = -9
Square it
(-9)^2 = 81
u^2- 18u +81 = (u-9)^2
Answer:
The blank should contain 81
Step-by-step explanation:
E = u^2 - 18u + (-18/2)^2
E = (u^2 - 18u + 9^2)
E = (u - 9)^2
To be perfectly correct what you have there is a perfect square, but you need to subtract out (9/2)^2 to make it a valid statement.
E = (u - 9)^2 - 81
Solve the triangle. round your answer to the nearest tenth
Answer:
∡A =41°
~~~~~~~~~~~~
BC=21
~~~~~~~~~~~~~~
sin(24)/AC=sin(41)/21
AC=13
~~~~~~~~~~~~~~
sin(115)/AB=sin(41)/21
AB=29
Step-by-step explanation:
A bank wishes to estimate the mean balances owed by customers holding Mastercard. The population standard deviation is estimated to be $300. If a 98% confidence interval is used and the maximum allowable error is $80, how many cardholders should be sampled?
A. 76
B. 85
C. 86
D. 77
Answer:
D. 77
Step-by-step explanation:
We have to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.98}{2} = 0.01[/tex]
Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].
That is z with a p-value of [tex]1 - 0.01 = 0.99[/tex], so Z = 2.327.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
The population standard deviation is estimated to be $300
This means that [tex]\sigma = 300[/tex]
If a 98% confidence interval is used and the maximum allowable error is $80, how many cardholders should be sampled?
This is n for which M = 80. So
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]80 = 2.327\frac{300}{\sqrt{n}}[/tex]
[tex]80\sqrt{n} = 2.327*300[/tex]
[tex]\sqrt{n} = \frac{2.327*300}{80}[/tex]
[tex](\sqrt{n})^2 = (\frac{2.327*300}{80})^2[/tex]
[tex]n = 76.15[/tex]
Rounding up:
77 cardholders should be sampled, and the correct answer is given by option d.
Solve 2x^2+5x+5=0 round solutions to the nearest hundredth.
Answer:
-0.56
Step-by-step explanation:
A newsstand spends $600 a month on rent and electricity, and it spends $2
for each magazine that it sells. The newsstand charges $5 for each
magazine. If n is the number of magazines, which equation represents the
profit function of the newsstand?
O A. p = 2n + 600
B. p = 3n-600
O c. p = 600n + 3
O D. p = 5n-600
Answer: B. p = 3n-600
Step-by-step explanation:
Cost = 2n + 600Earned = 5nProfit(p) = Earned - Cost
p = 5n - (2n + 600) = 5n - 2n - 600 = 3n - 600
The equation representing the profit function of the newsstand is
p = 3n - 600
Option B is the correct answer.
What is a function?A function has an input and an output.
A function can be one-to-one or onto one.
It simply indicated the relationships between the input and the output.
Example:
f(x) = 2x + 1
f(1) = 2 + 1 = 3
f(2) = 2 x 2 + 1 = 4 + 1 = 5
The outputs of the functions are 3 and 5
The inputs of the function are 1 and 2.
We have,
The revenue generated by selling n magazines is 5n dollars.
The cost of selling n magazines is the sum of the cost of purchasing n magazines and the fixed cost of rent and electricity, which is $2n + $600.
Now,
The profit function can be represented by:
p = revenue - cost
= 5n - (2n + 600)
= 3n - 600
Thus,
The equation representing the profit function of the newsstand is
p = 3n - 600
Learn more about functions here:
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round 12.5478 to the nearest hundredths
Answer:
12.04
Step-by-step explanation:
Find the number in the hundredth place 4 and look one place to the right for the rounding digit 1 . Round up if this number is greater than or equal to 5 and round down if it is less than 5 .
Drag each label to the correct location on the table. Each label can be used more than once. Match the attributes to the quadratic functions. x-intercept (-2,0) 1 y-intercept: 0,-8) minimum value: -1 axis of symmetry: 1 x-intercept: 2,0) y-intercept: (0,8) f(x) = x2 - 2x - 8 g(x) = x2 + 6x + 8 h(x) = -x2 + 2x
9514 1404 393
Answer:
f: x-intercept (-2, 0), y-intercept (0, -8), axis of symmetry x = 1g: x-intercept (-2, 0), y-intercept (0, 8), minimum value -1h: axis of symmetry x = 1Step-by-step explanation:
The equations can be written in factored form and vertex form to see the x-intercepts, axis of symmetry, and extreme value.
The y-intercept is the constant in the equation in standard form.
The axis of symmetry is the vertical line through the vertex.
__
f(x)f(x) = x² -2x -8 = (x -4)(x +2) = (x -1)² -9
x-intercept (-2, 0), y-intercept (0, -8), axis of symmetry x = 1
__
g(x)g(x) = x² +6x +8 = (x +2)(x +4) = (x +3)² -1
x-intercept (-2, 0), y-intercept (0, 8), minimum value -1
__
h(x)h(x) = -x² +2x = -(x)(x -2) = -(x -1)² +1
axis of symmetry x = 1
_____
Additional comment
We have only listed the intercepts, axis, and extreme where the values match a label.
How do you Find the acute Angle A when sinA=0.616?
Answer:
arcsin0.616
Step-by-step explanation:
arcsino.616
The scatterplot shows the average miles per gallon versus the age, in years, of a car.
A graph titled Fuel efficiency has age (years) on the x-axis, and miles per gallon on the y-axis. Points are at (1, 25), (2, 32), (3, 26), (4, 23), (5, 19), (6, 16), (7, 17), (8, 14), (9, 13), (10, 10).
If age was on the vertical axis and miles per gallon on the horizontal axis, how would the correlation change? Select all statements that would apply to the new correlation coefficient.
The sign would be the opposite.
The sign would remain the same.
It would have the same value.
It would become closer to 0.
It would become closer to 1.
(2 and 3) B,C
Answer:
The sign would remain the same.
It would have the same value.
ED2021
Answer: b&c
The sign would remain the same.
It would have the same value.
