Recall that variation of parameters is used to solve second-order ODEs of the form
y''(t) + p(t) y'(t) + q(t) y(t) = f(t)
so the first thing you need to do is divide both sides of your equation by t :
y'' + (2t - 1)/t y' - 2/t y = 7t
You're looking for a solution of the form
[tex]y=y_1u_1+y_2u_2[/tex]
where
[tex]u_1(t)=\displaystyle-\int\frac{y_2(t)f(t)}{W(y_1,y_2)}\,\mathrm dt[/tex]
[tex]u_2(t)=\displaystyle\int\frac{y_1(t)f(t)}{W(y_1,y_2)}\,\mathrm dt[/tex]
and W denotes the Wronskian determinant.
Compute the Wronskian:
[tex]W(y_1,y_2) = W\left(2t-1,e^{-2t}\right) = \begin{vmatrix}2t-1&e^{-2t}\\2&-2e^{-2t}\end{vmatrix} = -4te^{-2t}[/tex]
Then
[tex]u_1=\displaystyle-\int\frac{7te^{-2t}}{-4te^{-2t}}\,\mathrm dt=\frac74\int\mathrm dt = \frac74t[/tex]
[tex]u_2=\displaystyle\int\frac{7t(2t-1)}{-4te^{-2t}}\,\mathrm dt=-\frac74\int(2t-1)e^{2t}\,\mathrm dt=-\frac74(t-1)e^{2t}[/tex]
The general solution to the ODE is
[tex]y = C_1(2t-1) + C_2e^{-2t} + \dfrac74t(2t-1) - \dfrac74(t-1)e^{2t}e^{-2t}[/tex]
which simplifies somewhat to
[tex]\boxed{y = C_1(2t-1) + C_2e^{-2t} + \dfrac74(2t^2-2t+1)}[/tex]
In your biology class, your final grade is based on several things: a lab score, scores on two major tests, and your score on the final exam. There are 100 points available for each score. However, the lab score is worth 21% of your total grade, each major test is worth 25%, and the final exam is worth 29%. Compute the weighted average for the following scores: 60 on the lab, 81 on the first major test, 69 on the second major test, and 79 on the final exam. Enter your answer as a whole number.
Answer:
[tex]Weighted\ Average = 73[/tex]
Step-by-step explanation:
Given
[tex]Lab = 21\%[/tex]
[tex]Tests = 25\%[/tex]
[tex]Exam = 29\%[/tex]
[tex]Lab\ Score = 60[/tex]
[tex]First\ Test = 81[/tex]
[tex]Second\ Test = 69[/tex]
[tex]Exam = 79[/tex]
Required
The weighted average
To do this, we simply multiply each score by the corresponding worth.
i.e.
[tex]Weighted\ Average = Lab\ worth * Lab\ score + Tests\ worth * Tests\ score.....[/tex]
So, we have:
[tex]Weighted\ Average = 21\% * 60 + 25\% * 81 + 25\% * 69 + 29\% * 79[/tex]
Using a calculator, we have:
[tex]Weighted\ Average = 73.01[/tex]
[tex]Weighted\ Average = 73[/tex] --- approximated
Solve y = -7(-13)
I'm giving 30 points!
y = -7(-13)
=> y = -7 × (-13)
= y = 91
The highway department is testing two types of reflecting paint for concrete bridge end pillars. The two kinds of paint are alike in every respect except that one other is yellow. The orange paint is applied to 12 bridges, and the yellow paint is applied to 12 bridges. After a period of 1 year, reflectometer readings were made end pillars. (A higher reading means better visibility.) For the orange paint, the mean reflectometer reading was x19.4, with standard deviation s1-2.5. For the mean was X2-6.5, with standard deviation S2-2.4. Based on these data, can we conclude that the yellow paint has less visibility after 1 year?
Use a 10% level What are we testing in this problem?
a. difference of means
b. single proportion
c. difference of proportions
d. single mean
e. paired difference
Answer:
a. difference of means
Step-by-step explanation:
Given that :
Mean , x = 9.4
Standard deviation, [tex]s.d_1[/tex] = 2.5
Number, [tex]n_1[/tex] = 12
Mean, y = 6.5
standard deviation, [tex]s.d_2[/tex] = 2.4
Number, [tex]n_2[/tex] = 12
The null hypothesis is : [tex]$H_0: \mu_1=\mu_2$[/tex]
The alternate hypothesis is : [tex]$H_1: \mu_1>\mu_2$[/tex]
Level of significance, [tex]\alpha[/tex] = 0.1
From the [tex]\text{standard normal table, right tailed,}[/tex] [tex]$t_{1/2}$[/tex] = 1.363
Since out test is right tailed.
Reject [tex]H_0[/tex], if [tex]$T_0>1.363$[/tex]
We use the test statics,
[tex]$t_0=\frac{(x-y)}{\sqrt{\frac{s.d_1}{n_1}+\frac{s.d_2}{n_2}}}$[/tex]
[tex]$t_0=\frac{(9.4-6.5)}{\sqrt{\frac{6.25}{12}+\frac{5.76}{12}}}$[/tex]
[tex]$t_0=2.899$[/tex]
[tex]$|t_0|=2.899$[/tex]
[tex]\text{Critical value}[/tex]
The value of [tex]$|t_{1/2}|$[/tex] with minimum [tex]$\left(n_1-1,n_2-1)$[/tex] that is 11 df is 1.363
We go [tex]$|t_0|=2.899$[/tex] and [tex]$|t_{1/2}|$[/tex] = 1.363
Decision making:
Since the value of [tex]|t_0|>|t_{1/2}|$[/tex] and we reject the [tex]H_0[/tex]
The p-value : right tail [tex]H_a:(p>2.8988)[/tex]
= 0.00724
Therefore the value of [tex]$p_{0.1} > 0.00724$[/tex], and so we reject the [tex]H_0[/tex]
Thus we are testing 'the difference of means" in this problem.
Use the quadratic formula to find the solutions to the equation.
3x^2-10x+5=0
Answer:
option a is correct by using quadratic formula
A polygraph (lie detector) is an instrument used to determine if an individual is telling the truth. These tests are considered to be 90% reliable. In other words, if an individual lies, there is a 0.90 probability that the test will detect a lie. Let there also be a 0.045 probability that the test erroneously detects a lie even when the individual is actually telling the truth. Consider the null hypothesis, "the individual is telling the truth," to answer the following questions
a. What is the probability of a Type I error? (Round your answer to 3 decimal places.)
b. What is the probability of a Type II error? (Round your answer to 2 decimal places.
Answer:
A) P(Type I error) = 0.045
B) P(Type II) error = 0.1
Step-by-step explanation:
We are told that the reliability of the test is 90% reliable.
Also, we are told that the probability that the test erroneously detects a lie even when the individual is actually telling the truth is 0.045.
Thus;
A) To calculate the probability of type I error:
From statistics, in this question we can say that the probability of a type I error is the probability that the test will erroneously detect a lie even though the individual is actually telling the truth. Thus;
Probability of (type I error) = P(rejecting true null) = 0.045
B) For probability of type II error, it is defined as the error where we accept a null hypothesis that is false. We can say that it produces a false negative and the formula is;
P(Type II) error = 1 - reliability
Reliability in the question is 0.90
Thus;
P(Type II) error = 1 - 0.9
P(Type II) error = 0.1
Question 1 of 10
One advantage of a long-term loan compared to a short-term loan is that a
long-term loan:
A. does not require the borrower to have a good credit score.
O
B. can be paid off in full without the borrower paying any interest.
C. does not force the borrower to make payments every month.
D. allows a person to borrow more money at a lower interest rate.
Answer:
D. allows a person to borrow more money at a lower interest rate
A radio transmission tower is 180 feet high. How long should a guy wire be if it is to be attached to the tower 11 feet from the top and is to make an angle of 45° with the ground?
Answer:
Step-by-step explanation:
If enrollment increases by approximately the same
percentage between 2000 and 2010 as it decreased
between 1950 and 1960, what is the expected
enrollment in 2010?
Given:
The enrollment increases by approximately the same percentage between 2000 and 2010 as it decreased between 1950 and 1960.
To find:
The expected enrollment in 2010.
Solution:
Percentage decrease formula:
[tex]\%\text{ decrease}=\dfrac{\text{Initial value - New value}}{\text{Initial value}}\times 100[/tex]
The percentage decrease in between 1950 and 1960 is:
[tex]\%\text{ decrease}=\dfrac{4-3.5}{4}\times 100[/tex]
[tex]\%\text{ decrease}=\dfrac{0.5}{4}\times 100[/tex]
[tex]\%\text{ decrease}=\dfrac{50}{4}[/tex]
[tex]\%\text{ decrease}=12.5[/tex]
The enrollment decreased by 12.5% between 1950 and 1960. So, the enrollment increases by 12.5% between 2000 and 2010.
The expected enrollment in 2010 is:
[tex]\text{Expected enrollment}=7+\dfrac{12.5}{100}\times 7[/tex]
[tex]\text{Expected enrollment}=7+0.875[/tex]
[tex]\text{Expected enrollment}=7.875[/tex]
Therefore, the expected enrollment in 2010 is 7.875 thousands.
What is the range of the table of values
Answer:
Range: { 0,3,5,7,9}
Step-by-step explanation:
The range is the values that y takes
Range: { 0,3,5,7,9}
Now we have to find,
The range of the table of values,
→ Range = ?
Then the range will be the numbers that is in the Y column.
→ Range = ?
→ Range = (value that Y takes)
→ Range = 0,3,5,7,9
Therefore, the range is 0,3,5,7,9.
I really need help please
9514 1404 393
Answer:
60
Step-by-step explanation:
The minimum number required is the least common multiple (LCM) of 15 and 4. The numbers 15 and 4 have no common factors, so their LCM is their product.
15×4 = 60 strands are required
We have a study involving 5 different groups that each contain 9 participants (45 total). What two degrees of freedom would we report when we report the results of our study
Answer:
Degree of freedoms F(4,40)
Step-by-step explanation:
Given:
There is a study which is involving 5 different groups that each contains 9 participants (totally 45)
The objective is to calculate the degree of freedoms
Formula used:
Numerator degree of freedom = k-1
denominator degree of freedom=N-K
Solution:
Numerator degree of freedom = k-1
denominator degree of freedom=N-K
Where,
K= number of groups = 5
N= total number of observations
which is given as follows,
N=45
Then,
Numerator degree of freedom = k-1
=5-1
=4
Denominator degree of freedom = N-K
=45-5
=40
Therefore,
Degree of freedoms, F(4,40)
Can someone help me please..
Answer:
linear function
Step-by-step explanation:
Answer:
B
Step-by-step explanation:
The graph is a straight line, so it's a linear function.
Answer: B
There are 4 white and 5 red (indistinguishable) balls in a bag. Suppose you draw one ballout at a time without replacement and stop when you have drawn all the white (4 white) orall the red (5 red) balls. What is the probability that the last ball you drawn was a whiteball?
Answer:
5/9
Step-by-step explanation:
What we have in this question are four white balls and 5 red balls.
This is the sample space
[(4w,0R) (4w,1R)(4w,2R)(4w,3R)(4w,4R)(0w,5R)(1w,5R)(2w,5R)
So we have 9 possible sets of events
The event number with the last ball being white = 5
Probability of the last ball drawn being white = 5/9
= 0.56
Tara makes 30 cups of donut topping by mixing sugar and cinnamon. The ratio of sugar to cinnamon is 3:2
How much sugar did Tara use in the donut topping?
Answer:
18
Step-by-step explanation:
3:2 means 3/2 or 3÷2
but its better to leave it as
3/2
What is the domain of f(x)=(1/2)^x
Answer:
all real numbers
Algebra Examples
The domain of the expression is all real numbers except where the expression is undefined
Hello!
The domain of an exponential function is the crowd of all real numbers, so: x ∈ ℝ.
Good luck! :)
Optimal-Eats blender has a mean time before failure of 37 months with a standard deviation of 5 months, and the failure times are normally distributed. What should be the warranty period, in months, so that the manufacturer will not have more than 7% of the blenders returned
Answer:
The warranty period should be of 30 months.
Step-by-step explanation:
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.
Optimal-Eats blender has a mean time before failure of 37 months with a standard deviation of 5 months.
This means that [tex]\mu = 37, \sigma = 5[/tex]
What should be the warranty period, in months, so that the manufacturer will not have more than 7% of the blenders returned?
The warranty period should be the 7th percentile, which is X when Z has a p-value if 0.07, so X when Z = -1.475.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]-1.475 = \frac{X - 37}{5}[/tex]
[tex]X - 37 = -1.475*5[/tex]
[tex]X = 29.6[/tex]
Rounding to the nearest whole number, 30.
The warranty period should be of 30 months.
if TS is a midsegment of PQR find TS
Answer:
B. 7
Step-by-step explanation:
Recall: according to thee Mid-segment Theorem of a triangle, the Mid-segment of a triangle is half the length of the base of the triangle
Base length of the traingle, RQ = 14 (given)
Mid-segment = TS
Therefore,
TS = ½(RQ)
Plug in the value
TS = ½(14)
TS = 7
what is completely factored form or this expression?
y^2-12y+32
a.(y+4)(y+8)
b.(y-4)(y-8)
c.(y+18)(y+2)
d.(y-18)(y-2)
[tex]\\\\\\[/tex]
Therefore [tex]\sf{option~ B~ is ~correct }[/tex][tex]\sf{ }[/tex] [tex]\sf{ }[/tex] [tex]\sf{ }[/tex]
Answer:
(y-4) (y-8)
Step-by-step explanation:
y^2-12y+32
What two numbers multiply to 32 and add to -12
-8*-4 = 32
-8+-4 = -12
(y-4) (y-8)
5 times a number is 110 less than 7 times that number
Answer:
55
Step-by-step explanation:
let the number=x
5x=7x-110
7x-5x=110
2x=110
x=110/2=55
I need help with this.
Answer:
A and b Are in quadrant 2. F and D are in quadrant 1. F is in quadrant 3 and C is in quadrant 4
Step-by-step explanation:
each quadrant is in the boxes and the question is asking what is each coordinate is in what quadrant
Midsegments geometry acellus pls helppfpfpff
Answer:
BC = 28
Step-by-step explanation:
The midsegment DF is half the measure of the third side BC , then
BC = 2 × DF = 2 × 14 = 28
A teacher is paid an annual salary of $37.165. What is her gross monthly salary.
Answer:
3.01
Step-by-step explanation:
To Find :-
Monthly salary .SOLUTION :-
=> Monthly salary = $ 37.165/12= $ 3.01
John's age 4 years ago, if he will be y years old in 5 years
9514 1404 393
Answer:
y -9
Step-by-step explanation:
From 4 years ago until 5 years from now, John will age 9 years. That is, his age 4 years ago is 9 years less than it will be in 5 years.
John's age 4 years ago is y-9 years.
Will give brainliest.
Answer: Assuming there isnt a fourth answer, the answer is the second choice.
Step-by-step explanation: Point A is located in the first quadrant, Point B is located at 3, -1/2 and Point C is reflected off the y axis, in the second choice.
2•^2=?
A) -4
B) 1/4
C) 4
Answer:
1/4.
Step-by-step explanation:
2^-2 = 1/2^2
= 1/4.
If the two lines below are perpendicular and the slope of the red line is -7,
what is the slope of the green line?
10
10
A. 7
ОО
B. -7
C. 1
Answer:
C. ⅐
Step-by-step explanation:
Recall: the slope of a line that is perpendicular to another is the negative reciprocal of the slope of the other line that it is perpendicular to.
Thus:
Slope of red line = -7
The green line that is perpendicular to the red line will have a slope that is the negative reciprocal of -7.
Negative reciprocal of -7 = ⅐
The slope of the green line is therefore ⅐
Find the value of each expression:
1) 14 – 22
2) (10 + 5) – (32 – 3)
I need help pleaseeee
The yield in bushes per acre is related to the average temperature. The attached sample data was obtained in a recent study. The least-square regression equation for yield in bushes and the average temperature is
Region Temperature Yield (in bushes per acre)
1 4 3
2 8 7
3 10 8
4 12 10
5 9 8
6 6 4
Answer:
y = 0.9143x - 0.8
Step-by-step explanation:
Given the data :
Region Temperature Yield (in bushes per acre)
4 ______ 3
8 ______ 7
10 _____ 8
12 _____ 10
9 ______ 8
6 ______ 4
Using technology, the least square regression equation obtained by fitting the data is :
y = 0.9143x - 0.8
Where ;
y = predicted Bush yield, predicted variable
x = Average temperature, dependent variable
The slope Coefficient = 0.9143
The intercept = - 0.8
A recipe for chocolate chip cookies calls for 3 1/3 cups of flour. If you are making 2 1/4 recipes, how many cups of flour are needed.
Answer:
THIS IS THE ANSWER
Step-by-step explanation:
1 1/2 = 3/2
2 1/3 = 7/3
3/2 * 7/3 = 21/6 = 3 3/5 = 3 1/2 cups
PLEASE MARK ME AS A BRAINLIST!Is AABC-ADEF? If so, name which similarity postulate or theorem applies.
75
A. Similar - SSS
B. Similar - AA
0
C. Similar - SAS
D. Cannot be determined
Answer:
B. Similar - AA
Step-by-step explanation:
Two angles in ∆ABC are congruent to two corresponding angles in ∆DEF. Thus, it follows that the third pair of angles of both triangles would also be congruent.
Therefore, the three sides of ∆ABC and corresponding sides of ∆DEF will be proportional to each other.
This satisfies the AA Similarity Criterion. Therefore, ∆ABC ~ ∆DEF by AA.
