Answer:
Step-by-step explanation:
The original equation is [tex]121y''+110y'-24y=0[/tex]. We propose that the solution of this equations is of the form [tex] y = Ae^{rt}[/tex]. Then, by replacing the derivatives we get the following
[tex]121r^2Ae^{rt}+110rAe^{rt}-24Ae^{rt}=0= Ae^{rt}(121r^2+110r-24)[/tex]
Since we want a non trival solution, it must happen that A is different from zero. Also, the exponential function is always positive, then it must happen that
[tex]121r^2+110r-24=0[/tex]
Recall that the roots of a polynomial of the form [tex]ax^2+bx+c[/tex] are given by the formula
[tex] x = \frac{-b \pm \sqrt[]{b^2-4ac}}{2a}[/tex]
In our case a = 121, b = 110 and c = -24. Using the formula we get the solutions
[tex]r_1 = -\frac{12}{11}[/tex]
[tex]r_2 = \frac{2}{11}[/tex]
So, in this case, the general solution is [tex]y = c_1 e^{\frac{-12t}{11}} + c_2 e^{\frac{2t}{11}}[/tex]
a) In the first case, we are given that y(0) = 1 and y'(0) = 0. By differentiating the general solution and replacing t by 0 we get the equations
[tex]c_1 + c_2 = 1[/tex]
[tex]c_1\frac{-12}{11} + c_2\frac{2}{11} = 0[/tex](or equivalently [tex]c_2 = 6c_1[/tex]
By replacing the second equation in the first one, we get [tex]7c_1 = 1 [/tex] which implies that [tex] c_1 = \frac{1}{7}, c_2 = \frac{6}{7}[/tex].
So [tex]y_1 = \frac{1}{7}e^{\frac{-12t}{11}} + \frac{6}{7}e^{\frac{2t}{11}}[/tex]
b) By using y(0) =0 and y'(0)=1 we get the equations
[tex] c_1+c_2 =0[/tex]
[tex]c_1\frac{-12}{11} + c_2\frac{2}{11} = 1[/tex](or equivalently [tex]-12c_1+2c_2 = 11[/tex]
By solving this system, the solution is [tex]c_1 = \frac{-11}{14}, c_2 = \frac{11}{14}[/tex]
Then [tex]y_2 = \frac{-11}{14}e^{\frac{-12t}{11}} + \frac{11}{14} e^{\frac{2t}{11}}[/tex]
c)
The Wronskian of the solutions is calculated as the determinant of the following matrix
[tex]\left| \begin{matrix}y_1 & y_2 \\ y_1' & y_2'\end{matrix}\right|= W(t) = y_1\cdot y_2'-y_1'y_2[/tex]
By plugging the values of [tex]y_1[/tex] and
We can check this by using Abel's theorem. Given a second degree differential equation of the form y''+p(x)y'+q(x)y the wronskian is given by
[tex]e^{\int -p(x) dx}[/tex]
In this case, by dividing the equation by 121 we get that p(x) = 10/11. So the wronskian is
[tex]e^{\int -\frac{10}{11} dx} = e^{\frac{-10x}{11}}[/tex]
Note that this function is always positive, and thus, never zero. So [tex]y_1, y_2[/tex] is a fundamental set of solutions.
Tony rode his bicycle 3 7/10 miles to school. What is this distance written as a decimal?
Answer:
the distance written as a decimal is 3.7
37/10 = 3,7
Achievements :)
I need help with these questions please
Answer:
a) the graph has a minimum
b) (3, 0)
c) x=3
d) N/A
c) (0, 9)
*forgot how to solve for roots
Step-by-step explanation:
Desmos
Please answer this correctly
Answer:
4
Step-by-step explanation:
Set the height of the missing bar to 4 as there are 4 quantities between 21-25.
what is the value of x
14
15
16
17
Answer:
14
Step-by-step explanation:
Opposite angles in a rhombus are congruent. Even if you didn't know that, adding up the angles in this quadrilateral would tell you that ...
(5x)° = 70°
x = 70/5 = 14 . . . . . divide by 5
The value of x is 14.
.
A students received a score of 50 on his history test. The test had a mean of 69 and a standard deviation of 10. Find the z score and assess whether his score is considered unusual.
1.90; unusual
–1.90; not unusual
–1.90; unusual
1.90; not unusual
Answer:
c) The Z-score = - 1.90 unusual
Step-by-step explanation:
Explanation:-
Let 'X' be the random variable in normal distribution
Given student received a score X = 50
Mean of the Population x⁻ = 69
standard deviation of the Population 'σ' = 10
now
[tex]Z = \frac{x^{-}-mean }{S.D}[/tex]
[tex]Z = \frac{x^{-}-mean }{S.D} = \frac{50 -69}{10} = - 1.90[/tex]
The Z-score = - 1.90
Conclusion:-
The Z-score = - 1.90 unusual
Answer: The Z-score = - 1.90 unusual
Step-by-step explanation:
If log a = x and log b = y, then log (ab2) equals
1
1.
2 (x +y)
1
2.
x + 2 y
x + 2y
3
4.
2x + 2y
Su
uid Toolhar
Answer:
The answer for log(ab²) is x + 2y.
Step-by-step explanation:
You have to apply Logarithm Law,
[tex] log(a) + log(b) \: ⇒ \: log(a \times b) [/tex]
[tex] log( {a}^{n} ) \: ⇒ \: n log(a) [/tex]
In this question, you have to seperate it out :
[tex] log(a {b}^{2} ) = log(a) + log( {b}^{2} ) [/tex]
[tex] log( {b}^{2} ) = 2 log(b) [/tex]
[tex]let \: log(a) = x[/tex]
[tex]let log(b) = y[/tex]
[tex] log(a {b}^{2} ) = log(a) + 2 log(b) [/tex]
[tex] log(a {b}^{2} ) = x + 2y[/tex]
Plz help! U will get full points!
Answer:
2 wild cards
Step-by-step explanation:
Typical would mean most often
2 wild cards shows up 6 times which is most often
ملی
A man left one-fifth of his property to his
Son , one third to his daughter
and remaining
to his wife. If his wife got 35ooo RS what was the
worth of his total property?
Answer:
Rs 75,000
Step-by-step explanation:
Let the total value of property be x
If one-fifth of that is given to son
property with son = 1/5 of total value of property = 1/5 of x = x/5
If one-third of that is given to daughter
property with daughter = 1/3 of total value of property = 1/3 of x = x/3
remaining property after giving the portions to son and daughter
= total value of property - property with son -property with daughter
= x - x/5 - x/3
taking LCM of 5 and 3 (15)
= (15x - 3x - 5x)/15
= 7x/15
Given that remaining property was given to wife
property with wife = 7x/15
it is given that wife got 35000 Rs
thus,
7x/15 = 35,000
7x = 35,000*15 = 525,000
x = 525,000/7 = 75,000
Thus, total worth of property =Rs 75,000 Answer
Answer:
Rs 75,000
Step-by-step explanation:
Let the total value of property be x
If one-fifth of that is given to son
property with son = 1/5 of total value of property = 1/5 of x = x/5
If one-third of that is given to daughter
property with daughter = 1/3 of total value of property = 1/3 of x = x/3
remaining property after giving the portions to son and daughter
= total value of property - property with son -property with daughter
= x - x/5 - x/3
taking LCM of 5 and 3 (15)
= (15x - 3x - 5x)/15
= 7x/15
Given that remaining property was given to wife
property with wife = 7x/15
it is given that wife got 35000 Rs
thus,
7x/15 = 35,000
7x = 35,000*15 = 525,000
x = 525,000/7 = 75,000
Thus, total worth of property =Rs 75,000 Answer
Evaluate the function h(t) =|t +2| + 3; find h(6)
Answer:
11
Step-by-step explanation:
h(t) =|t +2| + 3
Let t=6
h(6) =|6 +2| + 3
= |8| +3
=8+3
= 11
Chris has been hired to assess a new version of a college entrance exam. He randomly assigns 100 high school juniors to take the new exam and 100 high school juniors to take the old exam. So that the participants were unaware of the two versions, the new exam was administered in the school gym while the old exam was administered in the school auditorium. The students taking the exam in the gym complained about the smell, the temperature and the uncomfortable seats. The students taking the exam in the auditorium made no complaints. Chris calculated a statistically significant difference between the two versions of the exam (t(198)= 3.1, p< 0.005) and concluded that the new exam was not a valid substitute for the old exam. There is a problem with validity. Which validity is weak in this example?
a. external validity
b. construct validity
c. statistical validity
d. internal validity
Answer:
Internal validity
Step-by-step explanation:
The internal validity here is weak
Internal validity describes the extent to which an evidence weighs the cause and effect claim. In this study, the internal validity that brought about failure in the new exam is mainly due to the environment where the exam was written and not the new exam itself.
So this validity is weak in claiming that the new exam is not a good substitute for the old exam.
Putting them in the same good environment might help the researchers to draw a better conclusion.
A bag contains some number of marbles. It is known that 20 of them are red. When 15 marbles are drawn, without replacement, we get 6 red. Assuming E(X)=6 red, what is the total number of marbles in the bag?
Answer:
The total number of marbles in the bag is 50.
Step-by-step explanation:
Here, we have n trials, without replacement. So the hypergeometric distribution is used.
The mean of the hypergeometric distribution is:
[tex]E(X) = \frac{n*k}{N}[/tex]
In which n is the number of items in the sample, k is the number of items in the population that are classified a success and N is the size of the population.
15 marbles are drawn:
This means that [tex]n = 15[/tex]
A bag contains some number of marbles. It is known that 20 of them are red.
This means that [tex]k = 20[/tex], since a success is drawing a red marble.
Assuming E(X)=6 red, what is the total number of marbles in the bag?
We have to find N when [tex]E(X) = 6[/tex]
So
[tex]E(X) = \frac{n*k}{N}[/tex]
[tex]6 = \frac{15*20}{N}[/tex]
[tex]6N = 300[/tex]
[tex]N = \frac{300}{6}[/tex]
[tex]N = 50[/tex]
The total number of marbles in the bag is 50.
What is an equation of the line that passes through the points (-7, -5) and
(-7, -2)?
Answer:
y=3x-1
Step-by-step explanation:
you first find the gradient
(-7,-5). (-7,-2)
x¹ y¹ x² y²
gradient=y²-y¹
x²-x¹
-2+5
-7+7
3/1=3. gradient is 3
equation formula= y=mx+c
(among the two sets of value you were given use one eg I will use -7 and -2)
y-(-7)/x-(-2)=3
y+7/x+2=3
y+7=3(x+2)
y+7=3x+6
y=3x+6-7
y=3x-1
Find the value of x:
What is the solution to y + 8.5 = 17.2?
Answer:
y+8.5 = 17.2
y = 17.2-8.5
= 8.7
Answer:
y+8.5 = 17.2
y = 17.2-8.5
= 8.7
Step-by-step explanation:
yes the answer above me is correct
please help !!!
Find the probability that x = -10
Answer:
20%
Step-by-step explanation:
Use the table provided... it says -10 is .2 which is the same as 20%
Answer:
0.20
Step-by-step explanation:
requires decimal not percentage
Please help thank you
Answer:
8000
Step-by-step explanation:
It's the only number missing from the answer to arrive at the answer itself :)
Answer:
8,000
Step-by-step explanation:
70 + x + 8 + 800,000,000 = 800,008,078 Add on the left side
800,000,078 + x = 800,008,078
-800,000,078 - 800,000,078 Subtract 800,000,078 from both sides
x = 8,000
Para cubrir un tejado rectangular de 29,7 m de largo ,se gastaron 24 552 locetas de 25cm x19 cm las cuales pierden al colocarse la 1/5 parte de su extensión eficaz . ¿ Qué ancho tenía el tejado ?
Answer:
El tejado tenía un ancho de 31.4 m.
Step-by-step explanation:
Tenemos un techo rectangular, con un largo de 29.7 m y un ancho x, que debemos calcular.
Entonces, la superficie del tejado es:
[tex]S=29.7x\;\,\text{[m}^2\text{]}[/tex]
Las locetas tienen una superficie de 25x19 cm, de las cuales 1/5 se pierde en la colocación. La superficie eficaz que ocupa cada loceta una vez colocada es:
[tex]S_L=(25\cdot19)\cdot(1-1/5)=475\cdot(0.8)=380\;\text{cm}^2[/tex]
Entonces, si se utilizaron 24552 locetas para cubrir todo el techo, podemos expresar la superfice del techo como:
[tex]S=24552\;\text{locetas}\;\cdot380\dfrac{\text{cm2}}{\text{loceta}}\cdot \left(\dfrac{1\text{m}}{100\text{cm}}\right)^2=\dfrac{24552\cdot380}{10000}\;\text{m2}=932.976\;\text{m2}[/tex]
Podemos calcular x igualando este último resultado con la primer ecuación:
[tex]S=29.7x=932.976\\\\x=932.976/29.7=31.413\approx31.4[/tex]
Alligators captured in Florida are found to have a mean length of 2 meters and a standard deviation of 0.35 meters. The lengths of alligators are believed to be approximately normally distributed. What percent of alligators have lengths greater than 2.2 meters?
Answer:
28.43% of alligators have lengths greater than 2.2 meters
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
[tex]\mu = 2, \sigma = 0.35[/tex]
What percent of alligators have lengths greater than 2.2 meters?
This is 1 subtracted by the pvalue of Z when X = 2.2. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{2.2 - 2}{0.35}[/tex]
[tex]Z = 0.57[/tex]
[tex]Z = 0.57[/tex] has a pvalue of 0.7157
1 - 0.7157 = 0.2843
28.43% of alligators have lengths greater than 2.2 meters
please need help asap!
Answer:
2/8 or 1/4
Step-by-step explanation:
There are 4 sections so if you spin it twice, we would double it so we have 2/8 and simplified to 1/4
I hope it helps you!
Use the formula v = u + at to find the velocity when the initial velocity is 3 m/s the acceleration is 1.5 m/s the time is 7 s
[tex]answer \\ 13.5 \: m/s \\ given \\ initial \: velocity(u) = \: 3 \: m/s \\ acceleration(a) = 1.5 \: m/s ^2\\ time(t) = 7 \: second \\ now \\ v = u + at \\ or \: v = 3 + 1.5 \times 7 \\ \: or \: v = 3 + 10.5 \\ v = 13.5 \: m/s \\ hope \: it \: helps[/tex]
The length of a rectangular driveway is five feet more than three times the width. The area is 350ft2. Find the width and length of the driveway.
Answer:
width -- 10 ftlength -- 35 ftStep-by-step explanation:
We can let x represent the width. Then the length will be represented by (3x+5), a value 5 more than 3 times the width.
The area is the product of length and width, so is ...
A = (3x +5)(x) = 3x^2 +5x
To make the area 350, we can find the value of x from ...
3x^2 +5x = 350
This can be solved a number of ways. One of them is "completing the square".
3(x^2 +5/3x) = 350
We choose to divide by 3 and add the square of half the x-coefficient.
x^2 +5/3x +(5/6)^2 = (350/3) + (5/6)^2
(x +5/6)^2 = 4225/36 . . . . simplify
x +5/6 = ±√(4225/36) = ±10 5/6 . . . . take the square root
x = 10 or -11 2/3 . . . . subtract 5/6
The positive solution is the one of interest: x = 10.
The driveway is 10 ft wide and 35 ft long.
I will mark you as BRANLIEST and I will give you 55 points if you answer correctly.
~Solve each system of equations using elimination. SHOW YOUR WORK
1) -4x+3y=-5
4x-5y=3
2) 2x+3y=36
10x-6y=12
Answer:
1. x = 2 y = 1
2. x = 17 y = 29/3
Step-by-step explanation:
1. Use elimination
-4x+3y=-5
4x-5y=3
x's cancel, so add them
-2y = -2
y = 1
substitute
4x -5(1) = 3
4x - 5 = 3
4x = 8
x = 2
2. Use elimination
2x+3y=36
10x-6y=12
Multiply top equasion by 5
10x+30y = 360
10x-6y = 12
x's cancel so subract
36y = 348
y = 29/3
Substitute
2x+3(2/3)=36
2x+2 = 36
2x = 34
x = 17
Can someone help me with this?
x^2-4x+4
I understand -2 x 2=-4, but I’m not seeing how to add the factors to get +4, because -2+2=0. I’ve got the first half of the solution, but not the second.
Answer:
(x-2)(x-2)
Step-by-step explanation:
You should be trying to find two numbers that add to make the coefficient of x (in this case, -4), and two numbers that multiply to make the constant term (in this case, +4). The two numbers that work for both of those criteria are -2 and -2.
-2 x -2 = +4 (satisfies the constant term)
-2 + -2 = -4 (satisfies the coefficient of x)
Suppose a company's revenue function is given by R(q) = - q^3 + 220q^2 and its cost function is given by C(q) = 500 + 13q, where q is hundreds of units sold/produced, while R(q) and C(q) are in total dollars of revenue and cost, respectively.
A) Find a simplified expression for the marginal profit function. (Be sure to use the proper variable in your answer.)
MP(q) =
B) How many items (in hundreds) need to be sold to maximize profits? (Round your answer to two decimal places.)
Answer:
A) MP(q) = -3q² + 440q - 13
B) 146.64 units.
Step-by-step explanation:
The profit function is given by the revenue minus the cost function:
[tex]P(q) = R(q) - C(q)\\P(q) = -q^3+220q^2-500-13q[/tex]
A) The Marginal profit function is the derivate of the profit function as a function of the quantity sold:
[tex]P(q) = -q^3+220q^2-500-13q\\MP(q) = \frac{dP(q)}{dq} \\MP(q)=-3q^2+440q-13[/tex]
B) The value of "q" for which the marginal profit function is zero is the number of items (in hundreds) that maximizes profit:
[tex]MP(q)=0=-3q^2+440q-13\\q=\frac{-440\pm \sqrt{440^2-(4*(-3)*(-13))} }{-6}\\q'=146.64\\q'' = - 0.03[/tex]
Therefore, the only reasonable answer is that 146.64 hundred units must be sold in order to maximize profit.
A factory received a shipment of 10 generators, and the vendor who sold the items knows there are 4 generators in the shipment that are defective. Before the receiving foreman accepts the delivery, he samples the shipment, and if too many of the generators in the sample are defective, he will refuse the shipment. Give answer as a decimal to three decimal places.
Answer:
A) 0.026
B) 0.130
Step-by-step explanation:
Complete Question
A factory received a shipment of 10 generators and the vendor who sold the items knows there are 4 generators in the shipment that are defective. Before the receiving foreman accepts the delivery, he samples the shipment, and if too many of the generators in the sample are defective, he will refuse the shipment. Give answer as a decimal to three decimal places.
(A) If a sample of 4 generators is selected, find the probability that all in the sample are defective.
(B) If a sample of 4 generators is selected, find the probability that none in the sample is defective.
Solution
A) This is a binomial distribution problem
Binomial distribution function is represented by
P(X = x) = ⁿCₓ pˣ qⁿ⁻ˣ
n = total number of sample spaces = number of generators to be picked = 4
x = Number of successes required = number of defective generators required = 4
p = probability of success = probability that a randomly selected generator is defective = (4/10) = 0.40
q = probability of failure = probability that a randomly selected generator is NOT defective = 1 - p = 1 - 0.40 = 0.60
P(X = 4) = ⁴C₄ (0.40)⁴ (0.6)⁴⁻⁴ = 0.0256 = 0.026 to 3 d.p.
B) n = total number of sample spaces = number of generators to be picked = 4
x = Number of successes required = number of defective generators required = 0
p = probability of success = probability that a randomly selected generator is defective = (4/10) = 0.40
q = probability of failure = probability that a randomly selected generator is NOT defective = 1 - p = 1 - 0.40 = 0.60
P(X = 0) = ⁴C₀ (0.40)⁰ (0.6)⁴⁻⁰ = 0.1296 = 0.130 to 3 d.p.
Hope this Helps!!!
Determine whether the sampling method is independent or dependent. A stock analyst wants to know if there is a difference between the mean rate of return from energy stocks and that from financial stocks. He randomly selects 13 energy stocks and computes the rate of return for the past year.
Answer:
The sampling method is independent.
Step-by-step explanation:
Samples are said to be dependent when the data chosen in one sample has an effect on the data to be chosen in the other sample, while samples are said to be independent if the data chosen in one sample has no effect on the data to be chosen on the other sample.
Here, the stock analyst wants to know if there is a difference between the mean rate of return from energy stocks and that from financial stocks, so, he randomly selects 13 energy stocks. Since the energy stocks he chose were randomly selected, it means the data he selected from the energy stock will not dictate the type of data to be selected from the financial stock. Thus, the sampling method is said to be independent.
Round $0.6683 to the nearest cent
Answer:
0.67
Step-by-step explanation:
0.668 is close to 0.67 than 0.66
A farmer planted corn in two different fields. He planted 500 seeds of regular corn in Field A and 500 seeds of experimental corn in Field B. At
harvest time, more ears of corn had grown in Field A than in Field B. The farmer concluded that more corn grew in Field A because of the type
of corn planted.
Choose two other possible variables that could have caused more corn to grow in Field A.
Answer:
1. More pollination process in the regular corn planted in field A than that of field B.
2. Low pest and insect attack on corn planted in field A compared to that of B.
Step-by-step explanation:
1. Pollination is the process in which a plant becomes fertilized, so as to produced seeds. The process requires some agent which could be; air, human, wind etc.
Therefore more pollination of the corn planted in field A than those in B would lead to more yield (ears of corn harvested) than that of B.
2. Pests and insects are agents which could reduce the yield of the corn after harvest. Comparing the two fields A and B, if the corn planted in field A were not affected by pests or insects, while those planted in B were affected, then more ears of corn would be harvested in field A.
Answer:
a,c, And gg gamer
Step-by-step explanation:
What value of c makes x2 + 6x + c a perfect square trinomial?
Answer:
9
Step-by-step explanation:
x^2 + 6x + c
Take the coefficient of x
6
Divide by 2
6/2 = 3
Square it
3^2 = 9
That is the value of c required
Answer:
C. 9
Step-by-step explanation:
c = 9
x² + 6x + 9
= (x+3)(x+3)
= (x + 3)²
it is a perfect square trinomial when c is equal to 9
what is tan B enter your answer as a simplified fraction in the box
Answer:
7/24
Step-by-step explanation:
Tangent is opposite over adjacent. You know that the opposite leg is 14 but you don't know the adjacent.
To find the unknown leg, use Pythagorean theorem so that 50^2-14^2= leg. The length is 48.
14/48= tan B
7/24= tan B