NOTE: Was not sure where to post this as it is a math question, but a part of my "Theoretical Physics" course.
I have no idea where to start this and am probably doing this mathematically incorrect.
given the function f(z) = cos(z+1/z) there should exist a singular point at z=0 as at z = 0...
I have been reading two books on complex analysis and my problem is that the two books give slightly different and possibly incompatible proofs that, for a function of a complex variable, differentiability implies continuity ...
The two books are as follows:
"Functions of a Complex Variable...
I'm kind of confused on how to evaluate the principal value as it's a topic I've never seen in complex analysis and all the literature I've read so far only deals with the formal definition, not providing an example on how to calculate it properly. Therefore, I think just understanding at least...
Hello! I have been searching the web and textbooks for a certain theorem which generalizes the value of the integral around a infinitesimal contour in the real axis, or also called indented contour over a nth order pole.
It is easy to prove that if the pole is of simple order, the value of the...
Hello,
I was interested in learning more about complex analysis. Also, very interested in analytic continuation. Can anyone recommend a good text that focuses on complex analysis.
Also, is there a good textbook on number theory that anyone recommends?
Thanks!
<mentor - edit thread title>>
Homework Statement
This is from a complex analysis course:
Find radius of convergence of
$$\sum_{}^{} (log(n+1) - log (n)) z^n$$
Homework Equations
I usually use the root test or with the limit of ##\frac {a_{n+1}}{a_n}##
The Attempt at a Solution
My first reaction is that this sum looks...
Homework Statement
Find all analytic functions ƒ: ℂ→ℂ such that
|ƒ(z)-1| + |ƒ(z)+1| = 4 for all z∈ℂ and ƒ(0) = √3 i
The Attempt at a Solution
I see that the sum of the distance is constant hence it should represent an ellipse. However, I am not able to find the exact form for ƒ(z). Any help...
Homework Statement
The following is a problem from "Applied Complex Variables for Scientists and Engineers"
It states:
The following integral occurs in the quantum theory of collisions:
$$I=\int_{-\infty}^{\infty} \frac {sin(t)} {t}e^{ipt} \, dt$$
where p is real. Show that
$$I=\begin{cases}0 &...
Say we have ##P_k(z)## a family of entire functions, and they depend analytically on ##k## in ##\Delta##. Assume ##P_k(z)## is nonzero on ##S^1## for all ##k##. How do I see that for each ##t \ge 0##, we have that$$\sum_{|z| < 1, P_k(z) = 0} z^t$$is an analytic function of ##k##? Here, the zeros...
I apologize in advance if any formatting is weird; this is my first time posting. If I am breaking any rules with the formatting or if I am not providing enough detail or if I am in the wrong sub-forum, please let me know.
1. Homework Statement
Using Euler's formula : ejx = cos(x) + jsin(x)...
1. Homework Statement
the problem is my answer for question (a) is not the same as the answer provided by the question, i get 2.81 - j4.49 Ω while the answer demands 2.81 + j4.49 Ω
Homework Equations
simplifying the circuit, details can be seen below
The Attempt at a Solution...
I am looking for an app that can instantaneously plot the function f(z) in the complex plane once z is given.
It would be much favorable if this process is fast which allows one to visualize f(z) when the user is moving the mouse on the complex plane to the location of z.
One possible...
When The denominator is checked, the poles seem to be at Sin(πz²)=0, Which means πz²=nπ ⇒z=√n for (n=0,±1,±2...)
but in the solution of this problem, it says that, for n=0 it would be simple pole since in the Laurent expansion of (z∕Sin(πz²)) about z=0 contains the highest negative power to be...
I have an equation that looks like
##i\dot{\psi_n}=X~\psi_n+\frac{C~\psi_n+D~a~\psi^\ast_{n+1}+E~b~\psi_{n+1}}{1+\beta~(D~\psi^\ast_{n+1}+E~\psi_{n+1})}##
where ##E,b,D,a,C,X## are constants. I have the ansatz
##\psi_n=A_n~e^{ixt}+B^\ast_n~e^{-itx^\ast}##, ##x## and ##A_n,B_n## are complex...
Homework Statement
Find a Laurent series of ##f(z)=ze^{1/z}## in powers of ##z-1##. Is there an easier way to go about this as this is not a typical expansion I see on textbooks. It seems that my incomplete solution is too complicated. Please help, exam is in two days and I am working on past...
Homework Statement
##\int_{0}^{2\pi} cos^2(\frac{pi}{6}+2e^{i\theta})d\theta##. I am not sure if I am doing this write. Help me out. Thanks!
Homework Equations
Cauchy-Goursat's Theorem
The Attempt at a Solution
Let ##z(\theta)=2e^{i\theta}##, ##\theta \in [0,2\pi]##. Then the complex integral...
Hey, I have been stuck on this question for a while:
I have tried to follow the hint, but I am not sure where to go next to get the result.
Have I started correctly? I am not sure how to show that the integral is zero.
If I can show it is less than zero, I also don't see how that shows it...
Homework Statement
Let ##f(z)## be an entire function of ##z \in \Bbb{C}##. If ##\operatorname{Im}(f(z)) \gt 0##, then ##f(z)## is a constant.
Homework Equations
n/a
The Attempt at a Solution
I don't get how the imaginary part of ##f(z)## would be greater than any number. Aren't complex...
Homework Statement
Let ##F## be an entire function such that ##\exists## positve constants ##c## and ##d## where ##\vert f(z)\vert \leq c+d\vert z\vert^n, \forall z\in \Bbb{C}##.
Is this question incomplete? My complex analysis course is not rigorous at all and this came up on a past final...
Homework Statement
Use an appropriate Laurent series to find the indicated residue for ##f(z)=\frac{4z-6}{z(2-z)}## ; ##\operatorname{Res}(f(z),0)##
Homework Equations
n/a
The Attempt at a Solution
Computations are done such that ##0 \lt \vert z\vert \lt 2##...
Homework Statement
Homework Equations
The relevant equation is that sqrt(z) = e^(1/2 log z) and the principal branch is from (-pi, pi]
The Attempt at a Solution
The solution is provided, since this isn't a homework problem (I was told to post it here anyway). I don't understand why the...
(mentor note: this is a homework problem with a solution that the OP would like to understand better)
In Taylor's Complex Variables,
Example 1.4.10
Can someone help me understand this? I don't know what they mean by (i, i inf), or how they got it and -it
I'm learning complex analysis right now, and I'm reading from Joseph Taylor's Complex Variables.
On Theorem 1.4.8, it says "If a log is the branch of the log function determined by an interval I, then log agrees with the ordinary natural log function on the positive real numbers if and only if...
Homework Statement
Show that
$$\int_C e^zdz = 0$$
Let C be the perimeter of the square with vertices at the points z = 0, z = 1, z = 1 +i and z = i.
Homework Equations
$$z = x + iy$$
The Attempt at a Solution
I know that if a function is analytic/holomorphic on a domain and the contour lies...
Hi. I have 2 questions regarding removable singular points.
1 - the residue at a removable singularity is always zero so by the residue theorem the integral around a closed simple contour is zero. Cauchy's theorem states the integral around a simple closed contour for an analytic function is...
The logic of the Feynman Propagator is confusing to me. Written in integral form as it is below
$$\Delta _ { F } ( x - y ) = \int \frac { d ^ { 4 } p } { ( 2 \pi ) ^ { 4 } } \frac { i } { p ^ { 2 } - m ^ { 2 } } e ^ { - i p \cdot ( x - y ) },$$
there are poles on the real axis. I have seen...
So folks, I'm learning complex analysis right now and I've come across one thing that simply fails to enter my mind: the Cauchy Integral Theorem, or the Cauchy-Goursat Theorem. It says that, if a function is analytic in a certain (simply connected) domain, then the contour integral over a simple...
Homework Statement
Find the domain in which the complex-variable function ##f(z)=(z+1)Ln(z)## is differentiable. Note: ##Ln(z)## is the principal complex logarithmic function.
Homework Equations
Cuachy-Riemann Equations?
The Attempt at a Solution
The solution I have in mind would be to let...
I have an expression
##\mathcal{Im}[RT^*e^{-2ip}]=|T|^2\sin p ##, where ##R=Ae^{ip}+Be^{-ip} ## and ##p ## is a real number.
This ultimately should lead to ##\mathcal{Im}[A+B+Te^{2ip}]=0 ## upto a sign (perhaps if I didn't do a mistake).
There is a condition on ##R ## that it is real...
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.
Lectures: http://www.nptel.ac.in/courses/111106094/
Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.Lectures: http://www.nptel.ac.in/courses/111106094/Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.Lectures: http://www.nptel.ac.in/courses/111106094/Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.Lectures: http://www.nptel.ac.in/courses/111106094/Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.Lectures: http://www.nptel.ac.in/courses/111106094/Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094
COPYRIGHT strictly reserved to Dr. T.E. Venkata Balaji (IIT Madras) and NPTEL, Govt of India. Duplication PROHIBITED.Lectures: http://www.nptel.ac.in/courses/111106094/Syllabus: http://www.nptel.ac.in/syllabus/syllabus.php?subjectId=111106094