Complex Definition and 1000 Threads

  1. r12214001

    Chemistry Complex ion oxidation state (with pic)

    question fig: solution manual: my solution: oxidation state of central cobalt is +6 due to 6 oxygen surrounding it,The other cobalt is +2 due to 2 oxygen surrounding it with NH3 ligand which is no count for oxidation state.
  2. A

    Complex analysis: find contradiction of a relationship

    I have reached a conclusion that no such z can be found. Are there any flaws in my argument? Or are there cases that aren't covered in this? Attempt ##\log(\frac{1}{z})=\ln\frac{1}{|z|}+i\arg(\frac{1}{z})## ##-\log(z)=-\ln|z|-i\arg(z)## For the real part...
  3. M

    Drawing sets of Complex Variables

    I tried saying z = x + iy, then squared both sides so that I would get something that looked like: |z - i|^2 + |z + i|^2 + |z - i||z + i| = 3, where the first two terms are simple but the third term is what I don't know what to do with. I'm wondering if I'm using the wrong approach. For that...
  4. K

    I Why the integral of a complex exponential can't be equal to zero?

    I was just playing with the integral ##\int e^{ixa}dx## when I found something interesting. If you integrate from ##x = m2\pi/a## to ##x = n2\pi/a## where ##m## and ##n## are any two integers, the integral equals zero. On one hand, as we can in principle choose whatever values we like for ##m##...
  5. J

    Solving a Complex Problem: Z_N, p(r), and Averages

    Hi everyone, I want to post this exercise and my attempt to a solution since there are a couple of points I am not entirely sure of and I might need your help. I'll address them while posting my solution 1) ##Z_N = (Z_1)^N##. I can evaluate ##Z_1## integrating with respect of both parts of the...
  6. G

    What is the complex conjugate of this wave function?

    I was planning to find the value of N by taking the integral of φ*(x)φ(x)dx from -∞ to ∞ = 1. However, this wave function doesn't have a complex number so I'm not sure what φ*(x) is. I was thinking φ*(x) is exactly the same φ(x), but with x+x0 instead of x-x0. Thank you
  7. BillTre

    Complex Series of Geologic Processes Generated Seizmic Humming

    I find this interesting. A pretty detailed description, of a complex geological series of events, that can't be directly seen. Here's my summary: In 2018 an usual humming was picked up by seismic equipment an island off Africa, a magma pool drained, flowed up a dyke, when horizontal, and then...
  8. L

    Solving a complex equation (damping/exponential-decay) like this....?

    ##e^{-0.6x}\sin{(5x)}-0.1=0## I have posted my graphical solution to this problem. But, how do I solve this numerically/mathematically without graphing it?
  9. S

    I Principal difference between complex numbers and 2D vectors revisited

    I know this topic was raised many times at numerous forums and I read some of these discussions. However, I did not manage to find an answer for the following principal question. I gather one deals with the same set in both cases equipped it with two different structures (it is obvious if one...
  10. I

    Expectation value of an angular momentum with a complex exponent

    I am struggling to figure out how to calculate the expectation value because I am finding it hard to do something with the exponential. I tried using Euler's formula and some commutator relations, but I am always left with some term like ##\exp(L_z)## that I am not sure how to get rid of.
  11. B

    B Complex number inequality question

    Z can be any point on the argand diagram so if z molous is less than 2 , is that somehow giving us the distance from origin? But how i assumed mod sign only makes things positive therefore its not sqrt( (x+yi)^2 ) = distance ??
  12. Math Amateur

    MHB Complex Function Theory: Explaining Example 1.5, Section 1.2, Chapter III

    I am reading Bruce P. Palka's book: An Introduction to Complex Function Theory ... I am focused on Chapter III: Analytic Functions, Section 1.2 Differentiation Rules ... I have yet another question regarding Example 1.5, Section 1.2, Chapter III ... Example 1.5, Section 1.2, Chapter III...
  13. D

    Rigid body simulation of complex mechanical systems

    Greetings, I'd like to simulate a complex mechanical automaton with lots of gears, cams, levers and springs. Most of the parts are going to be 3D printed except for some metal springs, rods and bearings. I want to make sure everything fits together and works as expected. Here is just a small...
  14. Math Amateur

    MHB Complex Square Root Function: Qs from Bruce P. Palka's Ex. 1.5, Ch. III

    I am reading Bruce P. Palka's book: An Introduction to Complex Function Theory ... I am focused on Chapter III: Analytic Functions, Section 1.2 Differentiation Rules ... I need further help with other aspects of Example 1.5, Section 1.2, Chapter III ... Example 1.5, Section 1.2, Chapter III...
  15. Math Amateur

    MHB Differentiating Complex Square Root Function: Bruce P. Palka, Ex. 1.5, Ch. III

    I am reading Bruce P. Palka's book: An Introduction to Complex Function Theory ... I am focused on Chapter III: Analytic Functions, Section 1.2 Differentiation Rules ... I need help with an aspect of Example 1.5, Section 1.2, Chapter III ... Example 1.5, Section 1.2, Chapter III, reads as...
  16. Math Amateur

    MHB Where Does the Sign of n Matter in Palka's Examples?

    I am reading Bruce P. Palka's book: An Introduction to Complex Function Theory ... I am focused on Chapter III: Analytic Functions, Section 1.2 Differentiation Rules ... I need help with some aspects of Examples 1.1 and 1.2, Section 1.2, Chapter III ... Examples 1.1 and 1.2, Section 1.2...
  17. Math Amateur

    MHB How is Equation (1) Equivalent to the Derivative Definition in Theorem 7.1?

    I am reading the book: "Theory of Functions of a Complex Variable" by A. I. Markushevich (Part 1) ... I need some help with an aspect of the proof of Theorem 7.1 ...The statement of Theorem 7.1 reads as follows: At the start of the above proof by Markushevich we read the following: "If f(z)...
  18. kuruman

    Insights SOHCAHTOA: Seemingly Simple, Conceivably Complex

    Continue reading...
  19. T

    What does it mean to have an complex transmission angle?

    I am getting a complex number for my transmission angle in part (c) but I do not know what that means. Am I even doing this correctly? Any help will be greatly appreciated. Thanks!
  20. F

    Geometric sum using complex numbers

    Solution to the problem tells us that ##S_5 + i S_6## is the sum of the terms of a geometric sequence and thus the solutions should be : $$S_5 = \frac{\sin( (n+1) x)}{\cos^n(x) \sin(x)},\,\,\,\, S_6 = \frac{\cos^{n+1}(x) - \cos((n+1)x)}{\cos^n(x) \sin(x)} , x \notin \frac{\pi}{2} \mathbb{Z}$$...
  21. arcTomato

    I Complex Fourier transform (represented by Σ)

    Dear all. I can't understand how to derive Eq.(2.3a). Fourier coefficients, ##A_j## and ##B_j## are described by summation in this paper as (2.2). I think this is weird. Because this paper said "In this section 2.1 ,the Fourier transform is introduced in very general terms". and I understand...
  22. UFSJ

    Courses Post doctoral opportunity in Complex Systems

    I'm looking for research projects in the study of complex system, meanly applied in social and biology problems. I would be so grateful with the indication of researchers in the theme. Thanks!
  23. Physics lover

    A tricky question with complex numbers

    All i was able to think was that i have to find a point (x,y) such that sum of its distances from points (0,0),(1,0),(0,1) and (3,4) is minimum.I tried by assuming the point to be centre of circle passing through any of the above 3 points,But it didn't helped me.
  24. Math Amateur

    MHB Verify Gamelin's Remark: Complex Square and Square Root Functions

    I am reading Theodore W. Gamelin's book: "Complex Analysis" ... I am focused on Chapter 1: The Complex Plane and Elementary Functions ... I am currently reading Chapter 1, Section 4: The Square and Square Root Functions ... and need some help in verifying a remark by Gamelin ... ... The...
  25. Math Amateur

    MHB Complex Derivative .... Remark in Apostol, Section 16.1 .... ....

    I am reading Tom M Apostol's book "Mathematical Analysis" (Second Edition) ... I am focused on Chapter 16: Cauchy's Theorem and the Residue Calculus ... I need help in order to fully understand a remark of Apostol in Section 16.1 ... The particular remark reads as follows: Could someone...
  26. S

    Solve polynomial using complex number

    I can do question (a). For question (b), I can not see the relation to question (a). Can we really do question (b) using result from (a)? Please give me little hint to relate them Thanks
  27. e101101

    Complex representation of a wave

    Homework Statement: Hi there, I'm currently taking an Optics course and the teacher is expecting us to have an understanding of the complex representation of waves. Although, hardly any of us have even heard of this yet. I've tried to google how to convert a cos(obj) and sin(obj) to an...
  28. Troxx

    I Trouble with infinity and complex numbers

    Summary: Trouble with infinity and complex numbers, just curious. I'm not too familiar with set theory ... but <-∞, ∞> contains just real numbers? Does something similar to <-∞, ∞> exist in Complex numbers? My question, is it "wrong"?
  29. F

    I Necessity of Complex Numbers in Quantum Mechanics

    Summary: Which properties of ##\mathbb{C}## are actually necessary? The following is speculative as well as a honestly meant question about the way QM is modeled. I don't want to create a new theory, just understand the necessities of the old one. Physicists use complex numbers for QM. But...
  30. jisbon

    What Is the Smallest Positive Argument for the Sum of Complex Roots of Unity?

    --Continued-- 7) Let ##\sum_{k=0}^9 x^k = 0## Find smallest positive argument. Same thing as previous question, but I guess I can expand to ##z+z_{2}+z_{3}+...+z_{9}=0## ##z=re^{iθ}## ##re^{iθ}+re^{2iθ}+re^{3iθ}+...## What do I do to proceed on? Cheers
  31. jisbon

    How Do You Solve Complex Number Equations in Quadratics and Exponentials?

    Hello all! Thanks for helping me out so far :) Really appreciate it. I don't seem to understand some of the questions presented to me, so if anyone has an idea on how to start the questions, please do render your assistance :) 4) Take ##3+7i## is a solution of ##3x^2+Ax+B=0## Since ##3+7i## is...
  32. jisbon

    Help Checking a Complex Numbers Problems

    Hello, here with some complex number questions which I need some assistance in checking :) 1) z=3+5i1+3iz=3+5i1+3i Find Re(z) and Im(z) My answer is 9595 and −25−25 respectively. Checked by Wolfram 2) Find principal argument of the complex numberz=−5+3iz=−5+3i and express it in radians up to 2...
  33. Math Amateur

    MHB Understanding Differentiability and Continuity in Complex Analysis

    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...
  34. D

    I What is the Topological Interpretation of Orders of Poles in Rational Functions?

    Hi. If I look at the function ## (z^2+z-2)/(z-1)^2## it appears to have a double pole at z=1 but if I factorise the numerator I get ##z^2+z-2 = (z+2)(z-1)## and it is a simple pole. Is it wrong to say it is a double pole ? If I overestimate the order of the pole in this case as 2 and...
  35. Math Amateur

    MHB Limits of Complex Functions .... Zill & Shanahan, Theorem 3.1.1/ A1

    I am reading the book: Complex Analysis: A First Course with Applications (Third Edition) by Dennis G. Zill and Patrick D. Shanahan ... I need some help with an aspect of the proof of Theorem 3.1.1 (also named Theorem A1 and proved in Appendix 1) ... The statement of Theorem 3.1.1 (A1) reads...
  36. jisbon

    Complex numbers: if (u+v)/(u-v) is purely imaginary, show that mod(u)=mod(v)

    I'm kind of stuck over here at one part, but something is telling me that it might be wrong too :( Do assist, thanks.
  37. D

    I How to know if a complex root is inside the unit circle

    Hi. I have been trying to calculate the real definite integral with limits 2π and 0 of ## 1/(k+sin2θ) ## To avoid the denominator becoming zero I know this means |k|> 1 Making the substitution ##z= e^{iθ}## eventually ends up giving me a quadratic equation in ##z^2## with 2 pairs of roots...
  38. D

    Is this complex function analytic?

    ## u_x = 3x^2 -3y^2 ## and ## v_y = -3y^2-3x^2 ## ## u_y = -6xy## and ## v_x = -6xy## To be analytic a function must satisfy ##u_x = v_y## and ##u_y = -v_x## Both these conditions are met by x=0 and y taking any value so I think the functions is analytic anywhere on the line x=0 However...
  39. D

    I Division of a complex number by zero

    Hi I know that division of a real number by zero is not defined. I just came across the following in a textbook on Complex Analysis by Priestley , " we are allowed to divide a complex number by zero as long as the complex number ≠ 0 " Is this correct ? What happens if the complex number is...
  40. alaspina

    Representing a complex oscillating system

    Hello, I have an equation relating the angular acceleration (d2Θ/dt2) of an undamped system to a forcing function and the an angular term (Θ). The system in question is an inverted pendulum. I know that such an oscillating system can be represented by the following function: The problem is...
  41. hilbert2

    Complex polynomial on the unit circle

    So, the values of polynomial ##p## on the complex unit circle can be written as ##\displaystyle p(e^{i\theta}) = a_0 + a_1 e^{i\theta} + a_2 e^{2i\theta} + \dots + a_n e^{ni\theta}##. (*) If I also write ##\displaystyle a_k = |a_k |e^{i\theta_k}##, then the complex phases of the RHS terms of...
  42. E

    Help Proving a Complex Laplace Transform

    So I could just try using the definition by taking the limit as T goes to infinity of ∫ from 0 to T of that entire function but that would be a mess. I tried breaking it down into separate pieces and seeing if I could use anything from the table but I honestly have no clue I'm really stuck. I'd...
  43. X

    Computing AC voltage in a complex filter

    Problem Statement: Computing AC voltage Relevant Equations: cut off frequency, ac voltage. Hey guys, Amazing to be in this group ! Please find attached the diagram of the problem. E = 10kV at 60Hz, C1 = 60pF and R1 = 1k. I have to compute the ac voltage in reference to ground at point [1]...
  44. Eclair_de_XII

    Showing that multiplication by a complex number is a linear transform

    If I had to guess what the complex matrix would look like, it would be: ##T(x+iy)=(xa-by)+i(ya+bx)=\begin{pmatrix} a+bi & 0 \\ 0 & -b+ai\end{pmatrix}\begin{pmatrix} x \\ y \end{pmatrix}## I'm not too sure on where everything goes; it's my first time fiddling with complex numbers, and moreover...
  45. E

    Why do snowflakes freeze into complex geometric patterns?

    Why do snowflakes freeze into complex geometric patterns?
  46. R

    Argument of a complex expression

    Problem Statement: What is the correct way of computing the argument of the following equation? Relevant Equations: I am trying to compute the argument ##\Phi## of the equation $$\frac{r-\tau\exp\left(i\varphi\right)}{1-\tau r\exp\left(i\varphi\right)} \tag{1}$$ which using Euler's equation...
  47. Pierson5

    Complex impedance and phase angle of a circuit

    I've attached my work below. The numbers seem odd to me though. Are my equations correct? Is the phase angle really (0/12)? If so, what are the implications of that?
  48. Robin04

    Calculating a complex integral

    As this function has no singularities the residue theorem cannot be applied. Can you help me a bit?
  49. Robin04

    Calculating the residue of a complex function

    The singularities occur at ##z = \pm i\lambda##. As ##\frac{d}{dz}(z^2+\lambda^2)^2|_{z=\pm i\lambda}=0##, these singularities aren't first order and the residues cannot be calculated with differentiating the denominator and evaluating it at the singularities. What is the general method to...
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