Carry out the following integrals, counterclockwise, around the indicated contour
Answers
For the first integral, z = π/4 is a pole of order 3 and lies inside the contour |z| = 1. Compute the residue:
[tex]\displaystyle \mathrm{Res}\left(\frac{e^z\cos(z)}{\left(z-\frac\pi4\right)^3}, z=\frac\pi4\right) = \lim_{z\to\frac\pi4}\frac1{(3-1)!} \frac{d^{3-1}}{dz^{3-1}}\left[e^z\cos(z)\right][/tex]
We have
[tex]\dfrac{d^2}{dz^2}[e^z\cos(z)] = -2e^z \sin(z)[/tex]
and so
[tex]\displaystyle \mathrm{Res}\left(\frac{e^z\cos(z)}{\left(z-\frac\pi4\right)^3}, z=\frac\pi4\right) = - \lim_{z\to\frac\pi4} e^z \sin(z) = -\frac{e^{\pi/4}}{\sqrt2}[/tex]
Then by the residue theorem,
[tex]\displaystyle \int_C \frac{e^z\cos(z)}{\left(z-\frac\pi4\right)^3} \, dz = 2\pi j \left(-\frac{e^{\pi/4}}{\sqrt2}\right) = \boxed{-\sqrt2\,\pi e^{\pi/4} j}[/tex]
For the second integral, z = 2j and z = j/2 are both poles of order 2. The second poles lies inside the rectangle, so just compute the residue there as usual:
[tex]\displaystyle \mathrm{Res}\left(\frac{\cosh(2z)}{(z-2j)^2\left(z-\frac j2\right)^2}, z=\frac j2\right) = \lim_{z\to\frac j2}\frac1{(2-1)!} \frac{d^{2-1}}{dz^{2-1}}\left[\frac{\cosh(2z)}{(z-2j)^2}\right] = \frac{16\cos(1)-24\sin(1)}{27}j[/tex]
The other pole lies on the rectangle itself, and I'm not so sure how to handle it... You may be able to deform the contour and consider a principal value integral around the pole at z = 2j. The details elude me at the moment, however.
Related Questions
Show that the equation y + 8 = 2(4x + 4) is linear and that it represents a proportional relationship between x and y.
Answers
Answer:
Step-by-step explanation:
y + 8 = 8x + 8
To convert from Standard Form to Slope-Intercept Form the strategy is to solve for which variable?
b
m
y
x
Answers
Answer: y
Step-by-step explanation:
Slope intercept form is written as
Y=mx+b, so you’d solve for the variable y
When solving negative one over five (x − 25) = 7, what is the correct sequence of operations?
Multiply each side by negative one over five, add 25 to each side
Multiply each side by 5, subtract 25 from each side
Multiply each side by negative one over five, subtract 25 from each side
Multiply each side by −5, add 25 to each side
Answers
Answer:
Multiply each side by −5, add 25 to each side.
Step-by-step explanation:
Mary has 18 ounces of apple chips she evenly portions the apple chips between four containers how many ounces of apple chips are in one container
Answers
Answer:
4.5 ounces
Step-by-step explanation:
18/4=4.5
4.5•4=18
Which of the following is most likely the next step in the series?
A.
B.
C.
D.
Answers
Each consecutive element of the series has one less blue points than the before element, with that, we conclude that the correct option is D, where there is only one blue point.
Which of the following is most likely the next step in the series?
Here we can see a series of 3 elements.
the first element is a circle with 4 blue points on its circumference, such that the points are connected to form a rectangle.
The next element is a circle with 3 blue points on it, such that when the points are connected a triangle is formed.
The third element is a circle, this time with 2 points, and the connection forms a segment.
So what we can see is that in each consecutive element the number of blue points on the circumference of the circles decreases by one, so the logical conclusion is that the next element will have only one point on its perimeter, then the correct option is D, where we can see only one blue point on the perimeter of the circle.
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Sammy's Chipmunk & Squirrel Observations
For a science project, Sammy observed a chipmunk and a squirrel stashing
acorns in holes. The chipmunk hid 3 acorns in each of the holes it dug. The
squirrel hid 4 acorns in each of the holes it dug. They each hid the same number
of acorns, although the squirrel needed 4 fewer holes. How many acorns did the
chipmunk hide?
Answers
Answer:12 accorns
Step-by-step explanation:
If they each hid the same number of acorns, although the squirrel needed 4 fewer holes, the chipmunk hid 3 acorns in each hole
Let's assume the number of holes the chipmunk dug is 'c', and the number of acorns it hid in each hole is 'x'. Similarly, let's assume the number of holes the squirrel dug is 's', and the number of acorns it hid in each hole is 'y'.
According to the information provided, the chipmunk hid 3 acorns in each of the holes it dug, so x = 3. The squirrel hid 4 acorns in each of the holes it dug, so y = 4.
Both the chipmunk and squirrel hid the same number of acorns, so cx = sy.
Also, the squirrel needed 4 fewer holes, so s = c - 4.
Now, we can use the information to set up a system of equations:
cx = sy
c - 4 = s
Substitute the value of s from the second equation into the first equation:
c(c - 4) = 3(c - 4)
Expand the equation:
c² - 4c = 3c - 12
Now, bring all terms to one side of the equation:
c² - 4c - 3c + 12 = 0
Combine like terms:
c² - 7c + 12 = 0
Now, factor the quadratic equation:
(c - 3)(c - 4) = 0
Now, set each factor to zero and solve for 'c':
c - 3 = 0 => c = 3
c - 4 = 0 => c = 4
Since the chipmunk hid 3 acorns in each hole, the correct answer is The chipmunk hid 3 acorns.
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Given the function f(x)=X^2- 3x, find f(-4)
Answers
-4 to the second power is 16 so it would be 16-(-12)= 28
What functions have a range of {y £ R | -
Answers
Answer:
the second and the fourth have a range of real no
I’ll give the crown thing
The band sold 456 pies in 2 weeks. Which proportion could be used to make the best estimate for the number of pies that will be sold in 12 weeks?
Answers
Answer:
i would say A. if its not a its B.
Step-by-step explanation:
Kevin and Randy Muise have a jar containing 80 coins, all of which are either quarters or nickels. The total value of the coins in the jar is $11.80. How many of each type of coin do they have?
Answers
Answer:
39 quarters and 41 nickelsStep-by-step explanation:
Let the number of quarters be x and nickels be y.
Given:
Quarter is 25 centsNickel is 5 centsNumber of coins is 80Total amount is $11.80 = 1180 centsWe have equations:
x + y = 8025x + 5y = 1180Solve the system by elimination, subtract 5 times the first equation from the second one:
25x + 5y - 5x - 5y = 1180 - 80*520x = 780x = 780/20x = 39Find the value of y:
39 + y = 80y = 80 - 39y = 41Verify:
25*39 + 5*41 = 975 + 205 = 1180(dy)/(dx) = (x ^ 2)/(1 + y)
Answers
Bye, hope this helps you succeed in school!
HELPPPPPPPPPPPPPPPPPPPPP
Answers
Answer: b
Step-by-step explanation: graph b is correct hope it helps
A company manufactures and sells personalized stationery. The weekly fixed cost is $3850 and it cost $3.00 to produce each package of stationery. The selling price is $6.50 per package. How many packages of stationery must be produced and sold each week for the company to generate a profit?
The company will generate a profit if;
more than or equal to
more than
less than or equal to
less than
|blank|packages of stationery are produced and sold each week.
(sorry forgot to add that part in last question, hope this one is better)
Answers
Answer:
more than 1100
Step-by-step explanation:
The contribution margin for each package sold is ...
$6.50 -3.00 = $3.50
The number of packages that must be sold to cover fixed costs is ...
3.50n > 3850
n > 1100 . . . . . . . divide by 3.50
The company will generate a profit if more than 1100 packages are produced and sold each week.
_____
Additional comment
If exactly 1100 packages are sold, then costs are covered, but profit is 0. In order for profit to be positive, more than 1100 packages must be sold.
What is the value of (-2.8)+0+(-2.6)+6.4
Answers
-2.8-2.6+6.4
-5.4+6.4
1
It cost Joseph $21.90 to send 146 text messages. How many text messages did he send if he spent $6.45?
Answers
Answer:
43 messages
Step-by-step explanation:
Given:
146 messages = $21.90
x messages = $6.45
Finding x by cross-multiplication:
x = 146*6.45/21.90 = 43
Hope this helps! :)
Let |u| = 10 at an angle of 45° and |v| = 13 at an angle of 150°, and w = u + v. What is the magnitude and direction angle of w?
|w| = 9.4; θ = 72.9°
|w| = 9.4; θ = 107.1°
|w| = 14.2; θ = 72.9°
|w| = 14.2; θ = 107.1°
Answers
Recall that for two vector x and y making an angle θ with each,
x • y = ||x|| ||y|| cos(θ)
If we replace y with x, we see that
x • x = ||x|| ||x|| cos(0) = ||x||² ⇒ ||x|| = √(x • x)
Using the last identity, the magnitude of w is
||w|| = √(w • w)
but since w = u + v, we have
w • w = (u + v) • (u + v)
The dot product distributes over sums and is commutative, so
w • w = (u • u) + (u • v) + (v • u) + (v • v)
… = ||u||² + 2 (u • v) + ||v||²
… = ||u||² + 2 ||u|| ||v|| cos(θ) + ||v||²
If u has a direction of 45° with the positive x-axis, v has a direction of 150°, then the angle between u and v is |45° - 150°| = 105°. So,
||w|| = √(||u||² + 2 ||u|| ||v|| cos(150°) + ||v||²)
… = √(10² + 2 • 10 • 13 cos(150°) + 13²)
… ≈ 14.2
Using the parallelogram rule for vector addition (see attached sketch), the sum of the angle between w and u and 45° is equal to the direction of w.
If φ is the angle between w and u, then
w • u = ||w|| ||u|| cos(φ)
… = 14.2 • 10 • cos(φ)
but we also have
w • u = (u + v) • u
… = (u • u) + (v • u)
… = ||u||² + ||u|| ||v|| cos(105°)
… = 10² + 10 • 13 • cos(105°)
… ≈ 66.4
Then
14.2 • 10 • cos(φ) ≈ 66.4
cos(φ) ≈ 0.467
φ ≈ 62.1°
and so the direction of w is 62.1° + 45° ≈ 107.1°.
i need help with this
Answers
Answer:
Yes Jeff is the correct answer
Step-by-step explanation:
F(x)=2x^2+7 what is the value f(-2)
Answers
Answer:
f(x)=2(x+7/4)^2-49/8
Step-by-step explanation:
what's 298,987 divided by 98?
Answers
Answer: 3050.8877551
Step-by-step explanation:
It is the policy of stores owned by the Talkara Co. to give out bonuses to salespeople every six months. The size of the bonus is determined by averaging (taking the mean of) the two highest and the lowest monthly sales totals from the six-month period, taking 8% of the result, and splitting it evenly among the salespeople. The graph below shows sales for the most recent bonus period.If there are six salespeople, how much money will each one receive, to the nearest dollar? a. $243 b. $309 c. $324 d. $355
Answers
Answer:
c. $324
Step-by-step explanation:
The solution is,
A) 83/400= 0,2075
B) 100/400=0,25
C) 42/400= 0,105
D) 42/100= 0,42
E) The special training program was effective.
What is division?Division can be stated as the process of splitting a number or an amount into equal parts. Division is one of the four basic operations of arithmetic, the ways that numbers are combined to make new numbers. The other operations are addition, subtraction, and multiplication.
here, we have,
Explanation:
Total population= 400 salespeople
Received a bonus last year= 83 salespeople
Attended a special sales training program= 100 salespeople
Both attended sales training and received a bonus= 42 salespeople
a) You need to calculate the number of salespeople that receive a bonus over total population
83/400= 0,2075 The proportion of salespeople that receive a bonus is 0,2075
b) You need to calculate the number of salespeople that attended a special program over total population
100/400= 0,25 The proportion of salespeople that attended a special program is 0,35
c) 42/400= 0,105 The proportion of salespeople that receive a bonus and attended a special program is 0,105
d) You need to calculate the proportion of people that having attended received a bonus.
42/100= 0,42 The proportion of salespeople that receive a bonus having attended a special program is 0,42
e) The special training program was effective. The proportion of people that receive a bonus over the total population that didn't attend the program (41/300=0,14) is inferior to the proportion of salespeople that attend the program and receive a bonus. Meaning that there are more chances of receiving a bonus taking a training program.
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Complete question:
A company employs 400 salespeople. Of these, 83 received a bonus last year, 100 attended a special sales training program at the beginning of last year, and 42 both attended the special sales training program and received a bonus. (Note: the bonus was based totally on sales performance.) a) What proportion of the 400 salespeople received a bonus last year? b) What proportion of the 400 salespeople attended the special sales training program at the beginning of last year? c) What proportion of the 400 salespeople both attended the special sales training program and received a bonus? d) What proportion of the salespeople who attended the special sales training program received a bonus? e) Based on your answers to parts a and d, does the special sales training program seem to have been effective? Explain your answer.
14. What's the least common denominator of 3/4, 4/5, and 2/3?
A. 60
B. 20
C. 15
D. 12
Answers
Help help help help math
Answers
Answer:
10.
Step-by-step explanation:
X is often associated with the value of "independent variable"
y=20-2(5)
y=20-10
y=10
Help help help help help math math math
Answers
Answer:
∠4 = 135°
Step-by-step explanation:
∠4 = the sum of the two remote angles in the triangle. (remote angles are the angles not next to ∠4
∠4 = 80° + 55°
∠4 = 135°
Answer:
<4 = 135
Step-by-step explanation:
I took this test
Solve for x/3= −9
SHOW WORK
Answers
Answer:
x =-27
Step-by-step explanation:
X/3= -9
or,X=-9×3(cross multiplication)
or, X=-27
Write and evaluate algebraic expressions
Answers
Answer:
9b+10s
Step-by-step explanation:
you are trying to find an expression for total cost after an unknown amount of hours. you need to multiply the number of hours (defined as b and s in this example) by the cost per hour given ($9/hr for the bike and $10/hr for the scooter).
this would result in the following expression: total cost=9b+10s
Your class is having a pizza party. You buy 5 pizzas Each pizz has 4 slices. How many slices is that altogether?
Answers
Answer:
20
Step-by-step explanation:
5 x 4 = 20
Answer: 20 slices of pizza
Step-by-step explanation:
you multiply 5 times 4
help with this please
Answers
y=-2*0+12 —> y=0+12 —> y=12
so you would put that 12 in the first box. that gives you the points (0,12) on the graph and that’s where you would put your first dot…
you repeat this process for all the other x values
Convert 65/36 radians to degree.
please help I'm stuck on this question.
Answers
See picture for solution.
Find the slope of
(7,-12) (1,3)
it's not -2/5 or 2/5 or 15/6
literally, if you solve this for me my depression will be no more
its been 3 days OF THIS ONE QUESTION
please, and thank you
Answers
Answer:
(8,-9)
Step-by-step explanation:
using the principle of vectors, you match each number to their coordinates and add them
so we have (7+1,-12+3)
which is equal to (8,-9)
Answer:
5/2
Step-by-step explanation:
Formula: y2-y1/x2-x1
Labeled:
(1,3)
1 = x2
3 = y2
(7,-12)
7= x1
-12 = x1
In order:
3+12 / 1-7
=15/6
which is simplified to 5/2
so when trying to find the slope of two points you want to use a certent formula which is y2 minus y1 over x2 minus x1 and if the x1 or y1 is negative it will be plus.
first you need to label them and then put them in the order you labeled them to the formula. After subtract or add and if you can simplify it then simplified it to get your answer.
this is the best way I can explain it, sorry
:(
PLEASE HELP ASAP mark brainlist
Answers
Answer:
whats the question, tell me it and i'll help you
Step-by-step explanation: