Recall that
[tex]\sin(x)=\displaystyle\sum_{n=0}^\infty(-1)^n\frac{x^{2n+1}}{(2n+1)!}[/tex]
Differentiating the power series series for y(x) gives the series for y'(x) :
[tex]y(x)=\displaystyle\sum_{n=0}^\infty a_nx^n \implies y'(x)=\sum_{n=1}^\infty na_nx^{n-1}=\sum_{n=0}^\infty (n+1)a_{n+1}x^n[/tex]
Now, replace everything in the DE with the corresponding power series:
[tex]y'-2xy = 6\sin(3x) \implies[/tex]
[tex]\displaystyle\sum_{n=0}^\infty (n+1)a_{n+1}x^n - 2\sum_{n=0}^\infty a_nx^{n+1} = 6\sum_{n=0}^\infty(-1)^n\frac{(3x)^{2n+1}}{(2n+1)!}[/tex]
The series on the right side has no even-degree terms, so if we split up the even- and odd-indexed terms on the left side, the even-indexed [tex](n=2k)[/tex] series should vanish and only the odd-indexed [tex](n=2k+1)[/tex] terms would remain.
Split up both series on the left into even- and odd-indexed series:
[tex]y'(x) = \displaystyle \sum_{k=0}^\infty (2k+1)a_{2k+1}x^{2k} + \sum_{k=0}^\infty (2k+2)a_{2k+2}x^{2k+1}[/tex]
[tex]-2xy(x) = \displaystyle -2\left(\sum_{k=0}^\infty a_{2k}x^{2k+1} + \sum_{k=0}^\infty a_{2k+1}x^{2k+2}\right)[/tex]
Next, we want to condense the even and odd series:
• Even:
[tex]\displaystyle \sum_{k=0}^\infty (2k+1)a_{2k+1}x^{2k} - 2 \sum_{k=0}^\infty a_{2k+1}x^{2k+2}[/tex]
[tex]=\displaystyle \sum_{k=0}^\infty (2k+1)a_{2k+1}x^{2k} - 2 \sum_{k=0}^\infty a_{2k+1}x^{2(k+1)}[/tex]
[tex]=\displaystyle a_1 + \sum_{k=1}^\infty (2k+1)a_{2k+1}x^{2k} - 2 \sum_{k=0}^\infty a_{2k+1}x^{2(k+1)}[/tex]
[tex]=\displaystyle a_1 + \sum_{k=1}^\infty (2k+1)a_{2k+1}x^{2k} - 2 \sum_{k=1}^\infty a_{2(k-1)+1}x^{2k}[/tex]
[tex]=\displaystyle a_1 + \sum_{k=1}^\infty (2k+1)a_{2k+1}x^{2k} - 2 \sum_{k=1}^\infty a_{2k-1}x^{2k}[/tex]
[tex]=\displaystyle a_1 + \sum_{k=1}^\infty \bigg((2k+1)a_{2k+1} - 2a_{2k-1}\bigg)x^{2k}[/tex]
• Odd:
[tex]\displaystyle \sum_{k=0}^\infty 2(k+1)a_{2(k+1)}x^{2k+1} - 2\sum_{k=0}^\infty a_{2k}x^{2k+1}[/tex]
[tex]=\displaystyle \sum_{k=0}^\infty \bigg(2(k+1)a_{2(k+1)}-2a_{2k}\bigg)x^{2k+1}[/tex]
[tex]=\displaystyle \sum_{k=0}^\infty \bigg(2(k+1)a_{2k+2}-2a_{2k}\bigg)x^{2k+1}[/tex]
Notice that the right side of the DE is odd, so there is no 0-degree term, i.e. no constant term, so it follows that [tex]a_1=0[/tex].
The even series vanishes, so that
[tex](2k+1)a_{2k+1} - 2a_{2k-1} = 0[/tex]
for all integers k ≥ 1. But since [tex]a_1=0[/tex], we find
[tex]k=1 \implies 3a_3 - 2a_1 = 0 \implies a_3 = 0[/tex]
[tex]k=2 \implies 5a_5 - 2a_3 = 0 \implies a_5 = 0[/tex]
and so on, which means the odd-indexed coefficients all vanish, [tex]a_{2k+1}=0[/tex].
This leaves us with the odd series,
[tex]\displaystyle \sum_{k=0}^\infty \bigg(2(k+1)a_{2k+2}-2a_{2k}\bigg)x^{2k+1} = 6\sum_{k=0}^\infty (-1)^k \frac{x^{2k+1}}{(2k+1)!}[/tex]
[tex]\implies 2(k+1)a_{2k+2} - 2a_{2k} = \dfrac{6(-1)^k}{(2k+1)!}[/tex]
We have
[tex]k=0 \implies 2a_2 - 2a_0 = 6[/tex]
[tex]k=1 \implies 4a_4-2a_2 = -1[/tex]
[tex]k=2 \implies 6a_6-2a_4 = \dfrac1{20}[/tex]
[tex]k=3 \implies 8a_8-2a_6 = -\dfrac1{840}[/tex]
So long as you're given an initial condition [tex]y(0)\neq0[/tex] (which corresponds to [tex]a_0[/tex]), you will have a non-zero series solution. Let [tex]a=a_0[/tex] with [tex]a_0\neq0[/tex]. Then
[tex]2a_2-2a_0=6 \implies a_2 = a+3[/tex]
[tex]4a_4-2a_2=-1 \implies a_4 = \dfrac{2a+5}4[/tex]
[tex]6a_6-2a_4=\dfrac1{20} \implies a_6 = \dfrac{20a+51}{120}[/tex]
and so the first four terms of series solution to the DE would be
[tex]\boxed{a + (a+3)x^2 + \dfrac{2a+5}4x^4 + \dfrac{20a+51}{120}x^6}[/tex]
I NEED THE ANSWER SOON PLEASE!!?!?! hopefully someone sees this
Answer:
1 and 1/25
Step-by-step explanation:
a bridge costs 94,500 to repair. if the state pays twice as much as the city, how much did each pay?
Exercise science researchers collecting data within their state noticed that teens who spend more time streaming videos spend less time exercising.
What are the explanatory variable and response variable for this relationship?
Explanatory variable: time spent exercising
Response variable: state of teen’s residence
Explanatory variable: time spent streaming videos
Response variable: time spent exercising
Explanatory variable: time spent exercising
Response variable: time spent streaming videos
Explanatory variable: state of teen’s residence
Response variable: time spent streaming videos
I think it is (B):
Explanatory variable: time spent streaming videos
Response variable: time spent exercising
Answer:
It is (B) ED2021
Explanatory variable: time spent streaming videos
Response variable: time spent exercising
A survey asked 50 students if they play an instrument and if they are in band.
1.25 students play an instrument.
2. 20 students are in band.
3. 30 students are not in band.
Which table shows these data correctly entered in a two-way frequency?
C, just look at the "Total" for each single information.
the values in the inner grid combine multiple informations.
The table shows these data correctly entered in a two-way frequency is table C.
What is Two way Frequency?Two-way frequency tables show the potential connections between two sets of categorical data visually. The table's four (or more) inside cells contain the frequency (count) data, which is displayed above and to the left of the table's designated categories.
We have been the information 25 students play an instrument 20 are in a band 30 are not in a band.
So, the two way table is:
Band Not in Band Total
Play instrument 20 5 25
Do not play instrument 0 25 25
Total 20 30 50
So, Table C is Correct.
Learn more about two-way frequency here:
https://brainly.com/question/9033726
#SPJ7
i will give brainliest help please
Answer:
SA = 52 square meters
Step-by-step explanation:
First, the equation I'll be using for this problem is SA=2(wl+hl+hw)! Our width is 4m, our length is 3m, and our height is 2m. To begin to solve this problem we are going to input these values in to the equation above.
SA = 2(4 × 3 + 2 × 3 + 2 × 4)
Next, we are going to multiply our values inside the parenthesis based on the PEMDAS strategy (if you have any questions about this, feel free to ask below :).
SA = 2(12 + 6 + 8)
Now, we can add our values inside the parenthesis.
SA = 2(26)
Finally, all we have to do is distribute the 2 outside of the parenthesis to inside the parenthesis.
SA = 52 square meters
Hope this Helps! :)
Have any questions? Ask below in the comments and I will try my best to answer.
-SGO
Để tuyển nhân viên, một công ty tổ chức kiểm tra 3 vòng độc lập. Một người tham gia thi tuyển với xác suất qua các vòng lần lượt là 0,8 và 0,6 và 0,25.
a) Tìm xác suất để người đó không được nhận vào công ty?
b) Tìm xác suất để người đó thi đỗ ít nhất 1 vòng.
c) Tìm xác suất để người đó thi không đỗ ở vòng 2.
Find the missing length indicated
Answer:
what's the question? ke
Craig and Cindy working together can mow the lawn in four hours working alone Cindy takes twice as long as Craig how long does it take Craig to mow the lawn alone
Answer:
12 hours
Step-by-step explanation:
1 : (1/4 : (2 + 1)) = 12
Mason conducted a survey of his class to determine if they prefer to use pens or pencils for their math homework. Out of the 30 students in his class, 12 of them are male. A total of 21 students said they prefer pencils, and 12 of those students are female.
Fill in the missing joint and marginal frequencies in the table.
Pencils Pens Total
Male
% 10% 40%
Female
% 20%
%
Total 70%
% 100%
Answer:
Step-by-step explanation:
-Total column
30 students in the class
12 male , so 30-12 = 18 female
-Pencils column
21 students prefer pencils
12 female that prefer pencils , 21-12 = 9 male that prefer pencils
-Total row
21 students prefer pencils
30 students total, 30-21 = 9 students prefer pens
-Pens column
12 students male -9 students male prefer pencil =3 students male prefer pens
18 students female -12 students female prefer pencil =6 students female prefer pens
-to calculate the % always find the equivalent fraction of
30 students/ 100% = number of students you have / ?%
example: for male that prefer pencils we have 30/100 = 9/? so
? = 100*9 /30 =30%
If b < 0 and a/b > c/b, then what is the relationship between a and c?
Answer:
a < cStep-by-step explanation:
Given inequality:
a/b > c/bSince b is negative, when multiplied by b, the inequality changes to opposite direction:
b(a/b) < b(c/b)a < c3. An elevator is moving upward with a speed of 14.3 m/s . Two seconds later, the elevator is still moving upward, but its speed bas been reduced to 3.7 m/s . What is the average acceleration of the clevator during the 2.0 interval?
By definition of average acceleration,
a (average) = (3.7 m/s - 14.3 m/s) / (2.0 s) = -5.3 m/s²
A study examines the relationship between being a registered nurse (yes/no) and passing a cultural competency exam (yes/no) among a group of 987 randomly selected employees at your hospital. What test would be appropriate to determine if there is an association
Answer:
The appropriate test to determine if there is an association between being a registered nurse and passing a cultural competency exam among a group of 987 randomly selected hospital employees is a:
Chi-square Test.
Step-by-step explanation:
The Chi-Square Test uses either a diagram (like a scatter plot) or a hypothesis test to show the existence of an association between two variables or statistically demonstrate that a relationship exists between the two variables. Using the computed t-score, the significant association between two categorical variables can be measured and established.
Last year, Singh had $20,000 to invest. He invested some of it in an account that paid 7% simple interest per year, and he invested the rest in an account that paid 6% simple interest per year. After one year, he received a total of $1280 in interest. How much did he invest in each account?
Answer:
8000 and 12000 respectively
Step-by-step explanation:
Let the amount invested in first account be x and y be the amount invested in the second account.
ATQ, x+y=20000 and 1280=(7/100)*x+(6/100)*y
x=8000 and y=12000.
What two numbers add to 13 and multiply to -48?
Answer:
16 x -3 and 16-3
Step-by-step explanation:
If you multiply 16 and -3 you get -48 and if you subtract 3 from 16 you get 13 (hope this helped) :)
Question 12 plz show ALL STEPS
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Answer:
θ = 1.5 radians ≈ 85.9°
Step-by-step explanation:
The arc length in terms of central angle and radius is ...
s = rθ
where θ is the central angle in radians. Here, we want to find θ, so we have ...
θ = s/r . . . . divide by r
For the given numbers, ...
θ = (6 cm)/(4 cm) = 3/2 = 1.5 . . . radians
I radian is 180°/π, so 3/2 radians is ...
(3/2)(180°/π) = 270°/π ≈ 85.9°
find the supplement of 158 degrees and 17 minutes
Answer:
supplement of 158 degree
x+158=180
x=180-158
x=22 degree.
Step-by-step explanation:
Which line segment has the same measure as ST?
RX
TX
SR
XS
Answer:
The answer is Line Segment SR.
Chris is buying new wood flooring for his house. The cost depends on the area of the floors.
Which is the dependent variable, and which is the independent variable?
Answer:
strong and fexible .
variable
What is the domain of f(x)=square root of 9-14x
Answer: 6.9
Step-by-step explanation:
I am struggling and I would be so happy if any of you helped me. Can someone help me with the last two red boxes please? The rest of the question is for reference to help solve the problem. Thank you for your time!
Answer:
I think you can go with:
The margin of error is equal to half the width of the entire confidence interval.
so try .74 ± = [ .724 , .756] as the confidence interval
Step-by-step explanation:
what is the formula to solve midpoint
Answer:
(x1 + x2) , (y1+y2)
2 2
Step-by-step explanation:
This graph shows a portion of an odd function.
Use the graph to complete the table of values.
X
f(x)
-2.
-3
-4
-6
DONE
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Answer:
-2-1-2-3Step-by-step explanation:
An odd function is symmetrical about the origin:
f(-x) = -f(x)
So, ...
f(-2) = -f(2) = -2
f(-3) = -f(3) = -1
f(-4) = -f(4) = -2
f(-6) = -f(6) = -3
Answer:
-2
-1
-2
-3
I did it on edge2020 and got it right
After running a mile a day over a period of two weeks, the average amount of weight loss is 2.5 pounds. A dietitian, who publishes health articles in a newspaper, states their new diet program helps with additional weight loss when combining their special diet with running a mile a day over a period of two weeks. Interested in studying the dietitian's article further, you ask friends who have tried the dietitian's new program and you determine their weight loss to be 3.0 pounds in a two week period, on average. As you set up a hypothesis test to determine if the dietitian's article is correct, what is the dietitian's claim?
a. Adults should run every day to lose weight.
b. The average amount of weight loss is less than 2.52.5 pounds.
c. The average amount of weight loss is greater than 3.03.0 pounds.
d. The average amount of weight loss is greater than 2.52.5 pounds.
Answer:
d. The average amount of weight loss is greater than 2.5 pounds.
Step-by-step explanation:
After running a mile a day over a period of two weeks, the average amount of weight loss is 2.5 pounds.
At the null hypothesis, we test if this mean is of 2.5, that is:
[tex]H_0: \mu = 2.5[/tex]
A dietitian, who publishes health articles in a newspaper, states their new diet program helps with additional weight loss.
With the additional weight loss, the dietitian claims that the mean is more than the value presented at the null hypothesis, that is, more than 2.5, and thus, the correct answer is:
[tex]H_1: \mu > 2.5[/tex]
And thus, the correct option is given by option d.
Which set of angles are complementary
Answer:
A. <ECF and <BCF
Step-by-step explanation:
Complementary angles are angles that add up to give 90°
m<BCE = m<BCA = 90° (right angles)
m<ECF + m<BCF = m<BCA
m<ECF + m<BCF = 90° (Substitution)
Therefore, <ECF and <BCF are complementary angles.
HELP PLEASE!!!
Oak wilt is a fungal disease that infects oak trees. Scientists have discovered that a single tree in a small forest is infected with oak wilt. They determined that they can use this exponential model to predict the number of trees that will be infected after t years.
f(t)=e^0.4t
Question:
Rewrite the exponential model as a logarithmic model that calculates the # of years, g(x) for the number of infected trees to reach a value of x.
The logarithmic model is:
[tex]g(x) = \frac{\ln{x}}{0.4}[/tex]
-------------
We are given an exponential function, for the amount of infected trees f(x) after x years.To find the amount years needed for the number of infected trees to reach x, we find the inverse function, applying the natural logarithm.-------------
The original function is:
[tex]y = f(x) = e^{0.4x}[/tex]
To find the inverse function, first, we exchange y and x, so:
[tex]e^{0.4y} = x[/tex]
Now, we have to isolate y, and we start applying the natural logarithm to both sides of the equality. So
[tex]\ln{e^{0.4y}} = \ln{x}[/tex]
[tex]0.4y = \ln{x}[/tex]
[tex]y = \frac{\ln{x}}{0.4}[/tex]
Thus, the logarithmic model is:
[tex]g(x) = \frac{\ln{x}}{0.4}[/tex]
A similar question is given at https://brainly.com/question/24290183
A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 5 students' scores on the exam after completing the course: 16, 21, 22, 12, 22
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Answer:
The critical value used is [tex]T_c = 2.132[/tex]
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
Step-by-step explanation:
Before building the confidence interval, we need to find the sample mean and the sample standard deviation.
Sample mean:
[tex]\overline{x} = \frac{16+21+22+12+22}{5} = 18.6[/tex]
Sample standard deviation:
[tex]s = \sqrt{\frac{(16-18.6)^2+(21-18.6)^2+(22-18.6)^2+(12-18.6)^2+(22-18.6)^2}{4}} = 4.45[/tex]
Confidence interval:
We have the standard deviation for the sample, so the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So
df = 5 - 1 = 4
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 4 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.132. The critical value used is [tex]T_c = 2.132[/tex]
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.132\frac{4.45}{\sqrt{5}} = 4.243[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 18.6 - 4.243 = 14.357
The upper end of the interval is the sample mean added to M. So it is 18.6 + 4.243 = 22.843.
The 90% confidence interval for the average net change in a student's score after completing the course is (14.357, 22.843).
Pls help
Minni is arranging 3 different music CDs in a row on a shelf. Create a sample space for the arrangement of a jazz CD (J), a pop CD (P), and a rock CD (R).
Given:
Minni is arranging 3 different music CDs in a row on a shelf.
To find:
The sample space for the arrangement of a jazz CD (J), a pop CD (P), and a rock CD (R).
Solution:
We know that the total number of ways to arrange n items is n!.
Minni is arranging 3 different music CDs in a row on a shelf. So, the total number of ways is:
[tex]3!=3\times 2\times 1[/tex]
[tex]3!=6[/tex]
The sample space for the arrangement of a jazz CD (J), a pop CD (P), and a rock CD (R) is:
{JPR, JRP, PJR, PRJ, RJP, RPJ}
Therefore, the required sample space is {JPR, JRP, PJR, PRJ, RJP, RPJ}.
Answer:
RPJ, JPR, PRJ, JRP, RJP, JPR.
Step-by-step explanation:
the graph of f(x)=6(.25)^x and its reflection across the y-axis , g(x), are shown. what is the domain of g(x)
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Answer:
all real numbers
Step-by-step explanation:
The domain of any exponential function is "all real numbers". Reflecting the graph across the y-axis, by replacing x by -x does not change that.
The domain of g(x) = f(-x) is all real numbers.
A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are defective.
a. Suppose a sample of 865 floppy disks is drawn. Of these disks, 112 were defective. Using the data, estimate the proportion of disks which are defective.
b. Suppose a sample of 865 floppy disks is drawn. Of these disks, 112 were defective. Using the data, construct the 95% confidence interval for the population proportion of disks which are defective.
Answer:
a) 0.1295
b) The 95% confidence interval for the population proportion of disks which are defective is (0.1071, 0.1519).
Step-by-step explanation:
Question a:
112 out of 865, so:
[tex]\pi = \frac{112}{865} = 0.1295[/tex]
Question b:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
For this problem, we have that:
[tex]n = 865, \pi = 0.1295[/tex]
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
The lower limit of this interval is:
[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.1295 - 1.96\sqrt{\frac{0.1295*0.8705}{865}} = 0.1071[/tex]
The upper limit of this interval is:
[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.1295 + 1.96\sqrt{\frac{0.1295*0.8705}{865}} = 0.1519[/tex]
The 95% confidence interval for the population proportion of disks which are defective is (0.1071, 0.1519).
Question 4
A sector of a circle has a diameter of 16 feet and an angle of 2pi 5 this is a fraction by the way) radians. What is the area of the sector?
Answer:
40.2
Step-by-step explanation:
Diameter = 16, Radius = 16/2 = 8
Central angle = 2π/5 radians = 72°
Sector area,
8²π×(72/360)
= 64π/5
= 40.2 (rounded to the nearest tenth)
Answered by GAUTHMATH
