I'll use the integrating factor method for the first DE, and undetermined coefficients for the second one.
(a) Multiply both sides by exp(7t ):
exp(7t ) dx/dt + 7 exp(7t ) x = 5 exp(7t ) cos(2t )
The left side is now the derivative of a product:
d/dt [exp(7t ) x] = 5 exp(7t ) cos(2t )
Integrate both sides:
exp(7t ) x = 10/53 exp(7t ) sin(2t ) + 35/53 exp(7t ) cos(2t ) + C
Solve for x :
x = 10/53 sin(2t ) + 35/53 cos(2t ) + C exp(-7t )
(b) Solve the corresonding homogeneous DE:
d²x/dt ² + 6 dx/dt + 8x = 0
has characteristic equation
r ² + 6r + 8 = (r + 4) (r + 2) = 0
with roots at r = -4 and r = -2. So the characteristic solution is
x (char.) = C₁ exp(-4t ) + C₂ exp(-2t )
For the particular solution, assume an ansatz of the form
x (part.) = a cos(3t ) + b sin(3t )
with derivatives
dx/dt = -3a sin(3t ) + 3b cos(3t )
d²x/dt ² = -9a cos(3t ) - 9b sin(3t )
Substitute these into the non-homogeneous DE and solve for the coefficients:
(-9a cos(3t ) - 9b sin(3t ))
… + 6 (-3a sin(3t ) + 3b cos(3t ))
… + 8 (a cos(3t ) + b sin(3t ))
= (-a + 18b) cos(3t ) + (-18a - b) sin(3t ) = 5 sin(3t )
So we have
-a + 18b = 0
-18a - b = 5
==> a = -18/65 and b = -1/65
so that the particular solution is
x (part.) = -18/65 cos(3t ) - 1/65 sin(3t )
and thus the general solution is
x (gen.) = x (char.) + x (part.)
x = C₁ exp(-4t ) + C₂ exp(-2t ) - 18/65 cos(3t ) - 1/65 sin(3t )
At a restaurant, the bill comes to $55. You decide to leave a 12
%
tip. How much did you leave for the tip?
Answer:
$6.60
Step-by-step explanation:
12% = 0.12
12% of $55 = 0.12 x 55
=6.6
So, $6.60
1. You are given the 3rd and 5th term of an arithmetic sequence. Describe in words how to determine the general term.
2. You are given the 3rd and 5th term of an geometric sequence. Describe how to determine the 10th term without finding the general term.
Step-by-step explanation:
1. In an arithmetic sequence, the general term can be written as
xₙ = y + d(a-1), where xₐ represents the ath term, y is the first value, and d is the common difference.
Given the third term and the fifth term, and knowing that the difference between each term is d, we can say that the 4th term is x₃+d and the fifth term is the fourth term plus d, or (x₃+d)+d =
x₃+2d. =x₅ Given x₃ and x₅, we can subtract x₃ from both sides to get
x₅-x₃ = 2d
divide by 2 to isolate d
(x₅-x₃)/2 = d
This lets us solve for d. Given d, we can say that
x₃ = y+d(2)
subtract 2*d from both sides to isolate the y
x₃ -2*d = y
Therefore, because we know x₃ and d at this point, we can solve for y, letting us plug y and d into our original equation of
xₙ = y + d(a-1)
2.
Given the third and fifth term, with a common ratio of r, we can say that the fourth term is x₃ * r. Then, the fifth term is
x₃* r * r
= x₃*r² = x₅
divide both sides by x₃ to isolate the r²
x₅/x₃ = r²
square root both sides
√(x₅/x₃) = ±r
One thing that is important to note is that we don't know whether r is positive or negative. For example, if x₃ = 4 and x₅ = 16, regardless of whether r is equal to 2 or -2, 4*r² = 16. I will be assuming that r is positive for this question.
Given the common ratio, we can find x₆ as x₅ * r, x₇ as x₅*r², and all the way up to x₁₀ = x₅*r⁵. We don't know the general term, but can still find the tenth term of the sequence
look at the image below forr the question plz
Answer:
[tex]308 \ m^3\\[/tex]
Step-by-step explanation:
The volume of a three-dimensional shape is the amount of space the figure takes up. This can be found by multiplying all of the dimensions of a figure together. In essence, the following formula can be used to find the volume.
[tex]A=l*w*h[/tex]
Where (l) represents the figure's length; (w) is the width: and (h) the height. Substitute the given values into the formula and solve for the volume.
[tex]A=l*w*h[/tex]
[tex]A=7*4*11[/tex]
Simplify,
[tex]A=7*4*11[/tex]
[tex]A=28*11[/tex]
[tex]A=308[/tex]
If f(x)=-4x-5 and g(x)=3-x whats is g(-4)+f(1)
Answer: -2
Step-by-step explanation:
g(-4) = 3 - (-4) = 3 + 4 = 7f(1) = -4(1) - 5 = -4 - 5 = -9g(-4) + f(1) = 7 + (-9) = 7 - 9 = -2
A log of wood weighs 120kg. After drying, it now weighs 80kg. Find the moisture content of the wood in percentage.
Answer: 33% is moisture content
Step-by-step explanation:
120kg - 80kg = 40kg
40 of 120 is %
Work:
40/120 = 0.33
0.33x100
= 33%
Round number to nearest tenth
Answer:
a= 13.5
c=18.7
B= 46
Step-by-step explanation:
Find two consecutive even numbers whose sum is 758.
Answer:
378 and 380
Step-by-step explanation:
The two even consecutive numbers that add up to 758 are going to be very close to half of 758. This is because two half of 758 are going to be the most similar addends of 758. This is important because the answers will be consecutive and therefore, must also be very similar. To solve, first, divide 758 by 2. This is 379, which is not an even number. So, to find the needed addends subtract and add 1 to 379. Both of these will be even and consecutive. These two numbers are 378 and 380. Then, to check you, can add them and see that they do sum 758.
Answer:
Step-by-step explanation:
Let the first number = x
Let the second number = x + 2
x + x + 2 = 758 Collect like terms
2x + 2 = 758 Subtract 2
2x = 758 - 2 Combine
2x = 756 Divide by 2
2x/2 = 756/2
x = 378
The first number is 378
The second number 380
If your teacher is really fussy, you can do it this way.
Let the first number = 2x
Let the second number = 2x + 2
The reason for this is to guarantee that both numbers were even to start with.
2x + 2x+2 = 758 Combine like terms
4x + 2 = 758 Subtract 2
4x = 756 Divide by 4
x = 756/4
x = 189
Therefore 2x = 378
2x + 2 = 380 Just as before.
Strontium-90 has a half-life of about 28 years. Which equation will solve the problem of how many grams of a 40 g sample
will remain after 84 years?
Oy = }(40)
y = {(40)
Oy = 40(1)
y = 40()
84
Answer:a0 = 40 mg
a1 = 20 mg after 28 years
a2 = 10 mg after another 28 years
Step-by-step explanation:Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Answer:
40 mg
Step-by-step explanation:
10 = 40 (1/2)t/28 and solve for t in years. 10/40 = (1/2)t/28 log(0.25) = (t/28) log(0.5) t = 28 log(0.25) / log(0.5) years = 56 years
(PLEASE HELP ITS URGENT)
What is the measure of angle x?
A) 60°
B) 30°
C) 45°
D) 90°
Answer:
B
Step-by-step explanation:
Reason...sum of angles in a triangle is equal to 180⁰
R+V+T=180⁰
60⁰+90⁰+x⁰=180⁰
150⁰+x⁰=180⁰
x⁰=180⁰-150⁰
:. x⁰=30⁰
===================================================
Explanation:
Ignore lines VS and SU. They're unnecessary clutter.
Triangle VRT is a right triangle with angles T = x, R = 60, V = 90
For any triangle, the angles must add to 180
T+R+V = 180
x+60+90 = 180
x+150 = 180
x = 180-150
x = 30
Or you could note that R+T = 90 Solves to T = 30 since triangle VRT is a right triangle. The rule with any right triangle is that the acute angles are always complementary (aka they add to 90 degrees).
write each of the following fraction as equivalent fractions with a denominator of 10 a. 1/2 b. 1/4 c. 3/30 d. 12/30
9514 1404 393
Answer:
a. 5/10
b. 2.5/10
c. 1/10
d. 4/10
Step-by-step explanation:
To find the numerator, multiply each fraction by 10.
a. (1/2)(10) = 5, so 1/2 = 5/10
b. (1/4)(10) = 2.5, so 1/4 = (2.5)/10 or (5/2)/10
c. (3/30)(10) = 1, so 3/30 = 1/10
d. (12/30)(10) = 4, so 12/30 = 4/10
A car dealership is advertising a car for $16,299.99. If the sales tax rate is 6.5 percent, what
is the total tax paid for the car?
A. S993 34
B. $1.000.00
CS1.059 50
DS1.359.19
Answer:
C.
Step-by-step explanation:
16,299.99*0.065=1059.50
the point a(2,-5) is reflected over the origin and its image is point b. what are the coordinates of point b
Answer:
b(-2,-5)
Step-by-step explanation:
Your help is very much appreciated I will mark brainliest:)
Answer:
B. Yes. By SSS~
Step-by-step explanation:
From the diagram given, we have the corresponding sides of both triangles as follows:
RQ/KL = 24/20 = 6/5
QP/LM = 18/15 = 6/5
RP/KM = 12/10 = 6/5
From the above, we can see that the ratio of the corresponding side lengths of both triangles are equal. This means that all three sides of one triangle are proportional to all corresponding sides of the other triangle.
The SSS similarity theorem states that if all sides of one triangle are proportional to all corresponding sides of another, then both triangles are similar to each other.
Therefore, ∆KLM ~ ∆RQP by SSS similarity.
Which fraction is greater than the fraction represented by the model?
HURRY PLS IM BEING TIMED!!!!
Answer:
7/16
Step-by-step explanation:
7/16>3/8
It would be 7/16 because 3/8 is what is being shown. If you make them both have a common denominator then it would be 6/16.
Use the diagram to answer the question below.
Name a point not on line AC
Answer:
It can be the point E or the point D
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
please give me correct answer
by picture
Answer:
hello,
a) answer: 600
b) answer: 840
Step-by-step explanation:
a)
20=2²*5,25=5²,30=2*3*5,40=2³*5
l.c.m(20,25,30,40)=2³*3*5²=8*3*25=800
b)
24=2³*3, 42=2*3*7,35=5*7
l.c.m=(24,42,35)=2³*3*5*7=840
Test scores are normally distributed with a mean of 68 and a standard deviation of 12. Find the z – score for a grade of 74. Round your answer to two numbers after the decimal.
Answer:
gang nem
Step-by-step explanation:
I need help guys thanks so much
Answer:
A. 243
Step-by-step explanation:
[tex] 81^\frac{5}{4} = (3^4)^\frac{5}{4} = 3^{4 \times \frac{5}{4}} = 3^5 = 243 [/tex]
Answer: A
I just simplified it to 3^5, and that is also 243.
Mixture Problem A solution contains 15 milliliters of HCI
and 42 milliliters of water. If another solution is to have
the same concentration of HCl in water but is to contain
140 milliliters of water, how much HCI must it contain?
Answer:
Step-by-step explanation:
This is a straight proportion problem.
15/42 = x/140 Cross Multiply
15*140 = 42 * x
2100 = 42x Divide by 42
2100/42 = x
x = 50 ml of HCl will be needed.
Find f(2) given f(x) = -3x^2 + 2x+11
Answer:
Answer:f(2)=-3(2)^2+2*2+11
Answer:f(2)=-3(2)^2+2*2+11 =-3*4+4+11
Answer:f(2)=-3(2)^2+2*2+11 =-3*4+4+11 =-12+4+11
Answer:f(2)=-3(2)^2+2*2+11 =-3*4+4+11 =-12+4+11 =3
hence, f(2)=3
Write an expression that represents the area of the rectangle. Remember A = LW
a)6x2−3x
b)9x2−3x
c)6x-1
d)12x - 2
Answer:
b) 9x² - 3x
Step-by-step explanation:
Area of a rectangle = Length × Width
Area for the rectangle = 3x - 1 × 3x
Area = [tex](3x-1)(3x)[/tex]
Step 1. Multiply by combining like terms
3x · 3x = 9x²
Step 2. Multiply -1 by 3x
-1 · 3x = -3x
Step 3. Combine 9x² and -3x
9x² - 3x
----------------------------------------------------------
doomdabomb: All brainliest and thanks are appreciated
and would mean a lot to me, thanks!
Answer:
The area of a triangle is always one half the base b times the height h.
SEE PICTURE BELOW;
If the base is represented by the expression 4x + 2 and the height is represented by 3x, which expression gives the area of the triangle?
9x 9x2 12x2 + 6x 6x2+ 3x ------->> CORRECTStep-by-step explanation:
Edge 2021
ANSWER PLS!! :DD
Which of the following is not a property of a regular pyramid?
A. lateral faces that are parallel
B. lateral faces that are congruent isosceles triangles
C. lateral edges that are congruent
D. volume of the pyramid is equal to one-third the product of the area of its base and its altitude
Answer:
a
Step-by-step explanation:
Lateral faces that are parallel is not a property of a regular pyramid. The correct option is A.
What is a regular pyramid?Any pyramid whose base is a regular polygon and whose lateral edges are all of the same lengths is said to be regular.
The properties of a regular pyramid are:-
Lateral faces that are congruent isosceles triangles. Lateral edges that are congruent and the volume of the pyramid is equal to one-third the product of the area of its base and its altitude.
Hence, option A is correct.
To know more about the regular pyramid follow
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In parallelogram ABCD,AB^4+AD^2+AB^2*AD^2=AC^2*BD^2.If angle ABC=x,find the product of all possible values of x
Answer:
Hello,
Step-by-step explanation:
AB=DC=b, AD=BC=a
p=BD, q=AC
angle ABC=x
[tex]AB^4+AD^4+AB^2*AD^2=AC^2*BD^2\\\\b^4+a^4+b^2a^2=(a^2+b^2+2abcos(X))(a^2+b^2-2abcos(X)\\\\(a^2+b^2+2a^2b^2)-a^2b^2=((a^2+b^2)^2-4a^2b^2*cos^2(X))\\\\\\4a^2b^2cos^2(X)=a^2b^2\\\\\\cos^2(X)=\dfrac{1}{4} \\\\(cos(X)-\dfrac{1}{2} )(cos(X)+\dfrac{1}{2} )=0\\cos(x)=\frac{1}{2} \ or\ cos(X)=\dfrac{-1}{2} \\\\\\X=60^o =\dfrac{\pi}{3} rad \ or \ X=120^o=\dfrac{4\pi}{3} rad\\\\\\\\Product=\dfrac{\pi}{3}*\dfrac{4\pi}{3} =\boxed{\dfrac{4\pi^2}{9}}\\[/tex]
Find the first five terms to an=2an-1+3, a1=6
Answer:
a1=6 a2=15 a3=33 a4=69 a5=141
Step-by-step explanation:
an=2an-1+3
We should attempt n=2 to find the second term
a2=2a1+3= 2*6+3=15
n=3 to find the third term
a3=2a2+3= 2*15+3=33
n=4 to find the fourth term
a4=2a3+3=2*33+3=69
n=5 to find the fifth term
a5= 2a4+3=2*69+3= 141
What effect will replacing x with (x−4) have on the graph of the equation y=(x−3)2 y = ( x − 3 ) 2 ?
Answer:
y"= 2 wich is positive
Step-by-step explanation:
Step-by-step explanation:
Our equation is: y=(x-3)²
x should be replaced by x-4
y=(x-3)²
y=[(x-4)-3]²
y=(x-4-3)²
y=(x-7)²
The graph is still a parabola but with a different vertex
The vertex here is :
y= (x-7)²
y= x²-14x-49
y'= 2x-14
solve y'=0
2x-14=0
2x=14
x=7
You can easily find it without derivating by dividing -14 by -2
since: x²-14x-49
a=1 b= -14 c=-49
-b/2a = 14/2 = 7
the image of 7 is:
y=(7-7)² = 0
so the coordinates of the new vertex are (7,0) and it's a maximum
since y">0
y'= 2x-14
y"= 2 wich is positive
Last question guys! Help help help
9514 1404 393
Answer:
slope 125, annual dues paymentStep-by-step explanation:
The two given points can be used to find the slope:
m = (y2 -y1)/(x2 -x1)
m = (650 -400)/(4 -2) = 250/2 = 125
The vertical axis is cost, and the horizontal axis is years, so the slope is the ratio of these: cost per year.
The slope of $125 per year is the yearly membership dues cost.
How many roots does the equation (8/(x^2 - 16) )+ 1 = 1/(x -4) have?
Plz show ALL STEPS
Answer:
Step-by-step explanation:
The graph of [tex]y = ax^2 + bx + c[/tex] is a parabola. The axis of symmetry is [tex]x = -b/2a[/tex]. What are the coordinates of the vertex?
The vertex can be written as:
(-b/2a, b^2/(4*a) - b^2/2a + c)
For a general parabola:
y = a*x^2 + b*x + c
We can write the vertex as:
(h, k)
The x-value of the vertex is the value of the axis of symmetry.
Then we have:
h = x = -b/2a
Now we need to find the y-value of the vertex.
To do that, we just replace the variable "x" by the x-value of the vertex in our equation, so we get:
k = y = a*(-b/2a)^2 + b*(-b/2a) + c
k = b^2/(4*a) - b^2/2a + c
Then the coordinates of the vertex are:
(h, k) = (-b/2a, b^2/(4*a) - b^2/2a + c)
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A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 421 gram setting. It is believed that the machine is underfilling the bags. A 43 bag sample had a mean of 414 grams. Assume the population standard deviation is known to be 19.
Required:
a. Is there sufficient evidence at the 0.1 level that the bags are underfilled?
b. Find the P-value of the test statistic.
Answer:
a) The p-value of the test is 0.0078 < 0.1, which means that there is sufficient evidence at the 0.1 level that the bags are underfilled.
b) 0.0078.
Step-by-step explanation:
Question a:
A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 421 gram setting.
At the null hypothesis, it is tested if the mean is of 421, that is:
[tex]H_0: \mu = 421[/tex]
It is believed that the machine is underfilling the bags.
At the alternative hypothesis, it is tested if the mean is of less than 421, that is:
[tex]H_a: \mu < 421[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
421 is tested at the null hypothesis:
This means that [tex]\mu = 421[/tex]
A 43 bag sample had a mean of 414 grams. Assume the population standard deviation is known to be 19.
This means that [tex]n = 43, X = 414, \sigma = 19[/tex]
Value of the test statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{414 - 421}{\frac{19}{\sqrt{43}}}[/tex]
[tex]z = -2.42[/tex]
P-value of the test and decision:
The p-value of the test is the probability of finding a sample mean below 414, which is the p-value of z = -2.42.
Looking at the z-table, z = -2.42 has a p-value of 0.0078.
The p-value of the test is 0.0078 < 0.1, which means that there is sufficient evidence at the 0.1 level that the bags are underfilled.
b. Find the P-value of the test statistic.
As found above, the p-value of the test statistic is 0.0078.
