Answers
1. The given equation is probably supposed to read
y'' - 2y' - 3y = 64x exp(-x)
First consider the homogeneous equation,
y'' - 2y' - 3y = 0
which has characteristic equation
r² - 2r - 3 = (r - 3) (r + 1) = 0
with roots r = 3 and r = -1. Then the characteristic solution is
[tex]y = C_1 e^{3x} + C_2 e^{-x}[/tex]
and we let y₁ = exp(3x) and y₂ = exp(-x), our fundamental solutions.
Now we use variation of parameters, which gives a particular solution of the form
[tex]y_p = u_1y_1 + u_2y_2[/tex]
where
[tex]\displaystyle u_1 = -\int \frac{64xe^{-x}y_2}{W(y_1,y_2)} \, dx[/tex]
[tex]\displaystyle u_2 = \int \frac{64xe^{-x}y_1}{W(y_1,y_2)} \, dx[/tex]
and W(y₁, y₂) is the Wronskian determinant of the two fundamental solutions. This is
[tex]W(y_1,y_2) = \begin{vmatrix}e^{3x} & e^{-x} \\ (e^{3x})' & (e^{-x})'\end{vmatrix} = \begin{vmatrix}e^{3x} & e^{-x} \\ 3e^{3x} & -e^{-x}\end{vmatrix} = -e^{2x} - 3e^{2x} = -4e^{2x}[/tex]
Then we find
[tex]\displaystyle u_1 = -\int \frac{64xe^{-x} \cdot e^{-x}}{-4e^{2x}} \, dx = 16 \int xe^{-4x} \, dx = -(4x + 1) e^{-4x}[/tex]
[tex]\displaystyle u_2 = \int \frac{64xe^{-x} \cdot e^{3x}}{-4e^{2x}} \, dx = -16 \int x \, dx = -8x^2[/tex]
so it follows that the particular solution is
[tex]y_p = -(4x+1)e^{-4x} \cdot e^{3x} - 8x^2\cdot e^{-x} = -(8x^2+4x+1)e^{-x}[/tex]
and so the general solution is
[tex]\boxed{y(x) = C_1 e^{3x} + C_2e^{-x} - (8x^2+4x+1) e^{-x}}[/tex]
2. I'll again assume there's typo in the equation, and that it should read
y''' - 6y'' + 11y' - 6y = 2x exp(-x)
Again, we consider the homogeneous equation,
y''' - 6y'' + 11y' - 6y = 0
and observe that the characteristic polynomial,
r³ - 6r² + 11r - 6
has coefficients that sum to 1 - 6 + 11 - 6 = 0, which immediately tells us that r = 1 is a root. Polynomial division and subsequent factoring yields
r³ - 6r² + 11r - 6 = (r - 1) (r² - 5r + 6) = (r - 1) (r - 2) (r - 3)
and from this we see the characteristic solution is
[tex]y_c = C_1 e^x + C_2 e^{2x} + C_3 e^{3x}[/tex]
For the particular solution, I'll use undetermined coefficients. We look for a solution of the form
[tex]y_p = (ax+b)e^{-x}[/tex]
whose first three derivatives are
[tex]{y_p}' = ae^{-x} - (ax+b)e^{-x} = (-ax+a-b)e^{-x}[/tex]
[tex]{y_p}'' = -ae^{-x} - (-ax+a-b)e^{-x} = (ax-2a+b)e^{-x}[/tex]
[tex]{y_p}''' = ae^{-x} - (ax-2a+b)e^{-x} = (-ax+3a-b)e^{-x}[/tex]
Substituting these into the equation gives
[tex](-ax+3a-b)e^{-x} - 6(ax-2a+b)e^{-x} + 11(-ax+a-b)e^{-x} - 6(ax+b)e^{-x} = 2xe^{-x}[/tex]
[tex](-ax+3a-b) - 6(ax-2a+b) + 11(-ax+a-b) - 6(ax+b) = 2x[/tex]
[tex]-24ax+26a-24b = 2x[/tex]
It follows that -24a = 2 and 26a - 24b = 0, so that a = -1/12 = -12/144 and b = -13/144, so the particular solution is
[tex]y_p = -\dfrac{12x+13}{144}e^{-x}[/tex]
and the general solution is
[tex]\boxed{y = C_1 e^x + C_2 e^{2x} + C_3 e^{3x} - \dfrac{12x+13}{144} e^{-x}}[/tex]
Related Questions
Beth had k dollars. She spent 8 dollars on a bag and the rest of the money on 4 notepads. Find the cost of each notepad in terms of k.
Answers
Answer:
Price of a notepad in terms of k ⇒ (k - 8)/4
Step-by-step explanation:
Let the price of a notepad be n.
8 + 4n = k
In order to get the answer, we've to make n as the subject of the above equation.
8 + 4n = k
4n = k - 8
n = (k - 8) / 4
A large grouper can weight 1/4 ton. how much does a large grouper weight to the nearest pound. [ please help ]
Answers
Answer:
500 pounds
Step-by-step explanation:
Step-by-step explanation:
To do this divide 2000 by 4.This will give you around 500.
Your school ID is a 5-digit number. The 9 is in the thousand place, the 0 is in the ones place, an 8 is in the thousands place, a 4 is in the tens place and a 2 is in the hundreds place. What is your school ID number?
Answers
Answer:
89240
Step-by-step explanation:
_ 9 _ _ _ is in the thousands
_ 9 _ _ 0 is in the ones
going to assume you meant 8 is in ten thousands
8 9 _ _ 0 is in ten thousands
8 9 _ 4 0 is in tens
8 9 2 4 0 is in hundreds
School number is 89240
Answer: 98,240
What we are doing here is changing from expanded form into standard form.
To do that, you add all the place values to get the total number. So, our place values are:
10,000 - Ten Thousands Place
1,000 - Thousands Place
100 - Hundreds Place
10 - Tens Place
Now, we will need to look at the problem.
It says, The 9 is in the ten thousand place, the 0 is in the ones place, an 8 is in the thousands place, a 4 is in the tens place and a 2 is in the hundreds place.
According to the question, the 9 will be in the Tens Thousands Place, so our first number will be, 90,000.
The 8 will be in the Thousands place, so our second number will be 8,000.
The 2 will be in the Hundreds place, so our third number will be 200.
The 4 will be in the Tens place, so our fourth number will be 40.
Since the one's place is 0, we don't need to worry about that number.
Putting the answer in an equation, it will be like this,
90,000 + 8,000 + 200 + 40Now we can add.
Adding these numbers up will equal to, 98,240.
Therefore, the answer is 98,240.
please help..........
THANKS!
Answers
74E10. La siguiente gráfica relaciona el precio a pagar en pesos por el número de horas en un estacionamiento público.
¿Cuál es el pago, en pesos, que se debe efectuar por haber dejado el carro en el estacionamiento 3 horas 15 minutos?
A)20 B)40 C)46 D)50
Answers
Usando una función lineal, se encuentra que el pago es:
C) 46
Una funcion lineal tiene el seguiente formato:
[tex]y = ax + b[/tex]
En que:
a eres lá inclinacion, o sea, la taja de cambio. b eres el intercepto, o sea, el valor de y cuando x = 0.En la gráfica, hay los puntos (0,20) y (5, 60), por eso:
El intercepto es [tex]b = 20[/tex]La taja es dada por el cambio en y dividido por el cambio en x, o sea:
[tex]a = \frac{60 - 20}{5 - 0} = 8[/tex]
Por eso:
[tex]y = 8x + 20[/tex]
Con 3 horas y 15 minutos, el tiempo es de 3.25 horas, puesto que [tex]\frac{15}{60} = 0.25[/tex], por eso:
[tex]y = 8(3.25) + 20 = 46[/tex]
Un problema similar es dado en https://brainly.com/question/24543328
Triangle A is a scaled version of triangle B. The dimensions of triangle A are twice the dimensions of triangle B. The area of triangle B is 40.5 sq cm. What is the area of triangle A?
Answers
Step-by-step explanation:
the lengths of any line (side, height,...) in A is twice as long as in B.
now, the area of a triangle is
baseline × height / 2
so, two lines are multiplied. that means the factor 2 gets multiplied in 2 times. and that means the area increases by the factor 2×2 = 4
therefore, the area of A is
40.5 × 4 = 162 cm²
What is 2x-3 when x=6
Answers
Answer:
0
Step-by-step explanation:
Problem 3: If a single six-sided die is rolled five times, what is the probability that a six is thrown exactly three times
Answers
Answer:
So the probability that a die thrown 5 times will result in a 6 exactly 3 times is 0.03215.
Step-by-step explanation:
HOPE IT HELPS I'M FILIPINO STUDENTS
Should the United States return to a gold standard? Why?
Answers
Answer:
No
Step-by-step explanation:
If the U.S goes in a gold standard it can put the whole state in a crises
The owner of a bookstore buys used books from customers for one dollar and 50 Cent each owner then resells the used books for 400% of the amount he paid for them what is the price of a used book in the bookstore?
Answers
1.50 x 4 = 6
tammy has soccer practice every 12 days, basketball 18 days, band practice 20 days, and music class every 24 days. If she has all these practices on the same day today, then how many days will it be until she has all four practices.
Answers
Answer:
360 days
Step-by-step explanation:
It would be a whole year until the classes line up on the same day again, because it would only be the exact same date of the next year that they line up.
Hope this helps!
Find the distance from point $A\left(15,-21\right)$ to the line $5x+2y\ =\ 4$ . Round your answer to the nearest tenth.
Answers
The distance from point (15,-21) to the line 5x + 2y = 4 is 27.5 units
Given the coordinate (15, -21) and the line 5x + 2y = 4
In order to get the point on the line 5x + 2y =4, we can a point on the line
Let x = 0
5(0) + 2y = 4
2y = 4
y = 2
The point (0, 2) is on the line.
Find the distance between the point (15, -21) and (0, 2) using the distance formula
[tex]D=\sqrt{(2+21)^2+(0-15)^2} \\D=\sqrt{23^2+15^2}\\D=\sqrt{754}\\D= 27.46units[/tex]
Hence the distance from point (15,-21) to the line 5x + 2y = 4 is 27.5 units
Learn more here: https://brainly.com/question/22624745
Dwayne read 3/8 of a chapter of his history book in 1/5 of an hour. At this rate, how many chapters of his history book can he read in 1 hour?
Answers
Answer:
1 7/8 (1, 2)
Step-by-step explanation:
60/5=12 so dwayne reads 3/8 chapter per 12 minutes
12/3=4 so dwayne reads 1/8 chapter per 4 minutes
4x8=32 dwayne reads a chapter per 32 minutes.
2x32=64 and got 4 minute extra which is the time for dwayne to read 1/8 chapter
So Dwayne can read 1 7/8 chapter in 1 hour, if rounding off then 2 chapters, if only an entire chapter counts then 1
Solve for x. Round your answer to the nearest tenth.
Answers
Answer:
-x + 20
Step-by-step explanation:
13-x+3+4
13 - x + 3 - 3 = 4 + 3
13 - x = 7
= -x + 7 + 13
= -x + 20
#Carry on LearningIf a crate of 250 apples costs $95, what is the unit cost
Answers
The unit cost of an apple in a crate of 250 apples is $2.63.
Given the following data:
Total number of apples in a crate = 250 applesCost of a crate of apple = $95To determine the unit cost of an apple:
In this exercise, you're required to calculate the cost of one apple in a crate, knowing that there are 250 apples in total at a cost of $95.
Thus, we would divide the total number of apples by the total cost of all the apples as follows:
[tex]Unit\;cost = \frac{Total\;apples}{Total\;cost}[/tex]
Substituting the given parameters into the formula, we have;
[tex]Unit\;cost = \frac{250}{95}[/tex]
Unit cost = $2.63
Read more on cost here: https://brainly.com/question/13214374
Is this triangle not similar because it only has two proportional sides?
Answers
Answer:
The triangles are similar.
Step-by-step explanation:
They share a common angle (∠S) and the ratio of the two sides is the same, i.e. SP/SQ = SR/ST
Find the difference between 11/5 and 5/2 on a number line
Answers
Answer:
Step-by-step explanation:
number line:
11 5
_ = 22/10 _ = 25/10
5 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
____________________________________________________________
10 1010 10 1010 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
5/2 is 3/10's bigger than 11/5
BRAINLIEST TO WHOEVER ANSWERS RIGHT
Answers
Answer:
the answer is -1 have a great day!
Step-by-step explanation:
Answer:
its D
D = IStep-by-step explanation:
The powers of i repeat in cycle of 4. For example, here are the first 4:
1: i
2: -1
3: -i
4: 1
If a number is divisible by 4, i to the power of that number would be 1. So, i^20 is 1, but we are multiplying it by i again, so the answer would be 1 * i = i
Got the answer from aklee18oo from brainly give him some credit
Which are shown on the diagram? Check all that apply.
Answers
Answer:
B C. F
Step-by-step explanation:
Frank is going to buy some ties
at $7.50 per tie and some shirts
at $18.50 per shirt. If he buys
twice as many ties as shirts and
spends no more than $205, what is the greatest number of shirts he
can buy? [All prices include tax.]
Answers
Answer:
6 shirts
Step-by-step explanation:
The cost of a shirt and 2 ties is ...
$18.50 +2(7.50) = $33.50
For $205, Frank can buy $205/$33.50 = 6.12 sets of shirt and ties.
Frank can buy 6 shirts (and 12 ties) for an amount less than $205.
_____
Additional comment
Frank's cost will be $201 for that purchase.
Find the values of all 6 trigonometric functions for the angle inside right triangle where the opposite side of the angle is 9 cm and hypothenuse of the triangle is 13 cm.
Answers
Answer:
See belowStep-by-step explanation:
Find the missing leg x first using Pythagorean:
[tex]x=\sqrt{13^2-9^2} =\sqrt{169-81} =\sqrt{88}[/tex]Now the 6 functions, considering angle α opposite to leg with length of 9:
sine = opposite/hypotenuse
sin α = 9 / 13cosine = adjacent/hypotenuse
cos α = √88 / 13tangent = opposite / adjacent
tan α = 9 / √88cotangent = adjacent / opposite
cot α = √88 / 9secant = hypotenuse / adjacent
sec α = 13 / √88cosecant = hypotenuse / opposite
csc α = 13 / 9B=
[tex]\\ \sf\longmapsto \sqrt{13^2-9^2}=\sqrt{169-81}=\sqrt{88}\approx9.5[/tex]
Now
[tex]\\ \sf\longmapsto sinA=\dfrac{P}{H}=\dfrac{9}{13}[/tex]
[tex]\\ \sf\longmapsto cosA=\dfrac{B}{H}=\dfrac{9.5}{13}[/tex]
[tex]\\ \sf\longmapsto tanA=\dfrac{P}{B}=\dfrac{9}{9.5}[/tex]
[tex]\\ \sf\longmapsto cotA=\dfrac{1}{tanA}=\dfrac{9.5}{9}[/tex]
[tex]\\ \sf\longmapsto secA=\dfrac{1}{cosA}=\dfrac{13}{9.5}[/tex]
[tex]\\ \sf\longmapsto cosecA=\dfrac{1}{sinA}=\dfrac{13}{9}[/tex]
WARM UP ACTIVITY (5 MIN) Ms. Chantel's car can go 228 miles on 6 gallons of gas. During a drive last week Ms. Chantel used 7 gallons of gas. a.) How far did she drive? b).Explain how the problem changes if you were given the distance Ms. Chantel drove last week instead of how much gas she used.
How does the problem change????
Answers
Answer:
a. 266
b. if you were given the distance you can just do, the distance divided by 38
Step-by-step explanation:
A. 228/6=38
228+38=266
12. A rectangular garden has a length of L meters and a width of 3 meters less than its length. How much does it cost to put a fence around the garden if the fencing is $4 per meter?
Answers
Answer:
Area: (2x - 7) * (3*2 + 4x)
(2x - 7) * (6 + 4x)
8x-42
Perimeter: 2(2x - 7) + 2(3*2 + 4x)
Step-by-step explanation:
hope this helps!
Can someone put an answer for each box plzzzz.
Answers
Holly ate 3 brownies from a pan with nine pieces what two equivalent fractions describe how much she ate?
Answers
Select all the statements that are true for △ABC.A. AH is an altitude.
B. IH is a median.
C. JC is a median.
D. The medians and altitudes intersect at the same point.
E. The altitudes intersect outside of the triangle.
Answers
The relationships between the two medians and an altitude marked on
ΔABC can be used to determine the true statements.
The true statements are;
A. AH is an altitudeC. JC is a medianReasons:
A median line is a line that extends from the vertex to the midpoint of the
opposite side, bisecting the opposite side.
In the figure, we have;
The median of ΔABC are; JC, and BI
The point of intersection is the point K
The altitude is a perpendicular line from a vertex to the opposite side
known as the base of the triangle.
The given altitude of ΔABC is; AH
Therefore, the statements that are true are;
A. AH is an altitude
C. JC is a median
Learn more about the median line and altitude of a triangle here:
https://brainly.com/question/2141396
https://brainly.com/question/4420798
20. True or False
When you multiply or divide
by a negative number, you
flip the sign
Answers
Answer:
That is true
You must flip the sign when you are multiplying or dividing by a negative number
What is the equation of the line in slop-intercept form?
Enter your answer in the blank spots
y= __x + __
Answers
Answer:
y = 2 1/2 x + 5
Step-by-step explanation:
We were recently going over this. Slope formula: y2 - y1 / x2 - x1. In our case the slope is 2 1/2, and the y-intercept is 5.
Tell me if I'm wrong :)
geomtry plz help 15 points
Answers
Answer:
it should be 60°. the single marks on each side means they are all equal
Answer:
m∠L=60º
Step-by-step explanation:
The triangle is an equilateral triangle meaning that all angles and sides are equal.
m∠L=60º
Hope this helps :)
Help please i need to know this answer
Answers
Answer:
976
SA=2(S1)+2(S2)+S3
S1=14*24/2
S1=168
S2=25*10
S2=250
S3=14*10
S3=140
SA=2(168)+2(250)+140
SA=976 cm
