Numbers Definition and 1000 Threads

  1. Einstein's Cat

    Multiplying and dividing real and complex numbers

    Is it possible to divide and multiply complex numbers and real numbers and if so, how does one do that? If not, why so? Cheers for your help!
  2. C

    Quantiles on a stream of real numbers

    I need to calculate some quantiles for a sample of 108 real numbers with unknown mean and unknown variance. I currently store and sort those numbers, but I would try a streaming method where the numbers are not stored. In a paper is written: "If the size of the input stream, N is known, then the...
  3. barbara

    MHB Proving an Equivalence Relation on Real Numbers

    I know that 1. To show the relation is reflexive, we need to show that for any x, using the definition of R, we have xRx. The definition of R means that we must have |x - x| is even.2. To show that R is symmetric, we would have to show that if xRy then yRx. In the context of the definition...
  4. DaveC426913

    Explaining imaginary numbers to laypeople

    I've had discussions with laypeople (of which, I am one) about real-world manifestations of imaginary numbers. We can never seem to find a satisfactory, concise example. I know they are used in real-world calculations for things like EM wavelengths in electronics, but if you aren't into...
  5. toforfiltum

    Inequalities of negative arguments in complex numbers

    Homework Statement Arg z≤ -π /4 Homework EquationsThe Attempt at a Solution I'm confused whether the answer to that would be more than -45° or less. Should the approach to arguments be the same as in negative numbers?
  6. kalimaa

    A Relationship between Quantum Numbers and Quantum Information

    I would appreciate any clarification (or opinion) on the relationship between Quantum Numbers and Quantum Information. My question is related to the puzzle wether matter merely represents information or - at the basement level of reality - actually can be said to be information. Just to give...
  7. S

    Has it been proven that all rational numbers repeat ....

    in every radixial representation, except of course for those cases in which the numerator is a factor of some natural-number power of the radix? For the radixial system we know (i.e., because we are bilateral and have arms that have 5 fingers), this would mean that any possible natural number...
  8. R

    Some seat numbers missing on flight

    Why some row numbers like 13 ( know the reason of unlucky number), 18, 19, 20, 21, 32, 33 and 42 are missing on flights?
  9. T

    MHB Beginner Exercises on Prime numbers and Equality / Inequality proofs

    Does anyone know a good resource for exercises on these topics?
  10. squelch

    Complex Numbers and Constants of Integration

    Homework Statement Suppose that the characteristic equation to a second order, linear, homogeneous differential equation with constant coefficients yielded two complex roots: \begin{array}{l} {\lambda _1} = a + bi\\ {\lambda _2} = a - bi \end{array} This would yield a general solution of: y =...
  11. PengKuan

    Cardinality of the set of binary-expressed real numbers

    Cardinality of the set of binary-expressed real numbers This article gives the cardinal number of the set of all binary numbers by counting its elements, analyses the consequences of the found value and discusses Cantor's diagonal argument, power set and the continuum hypothesis. 1. Counting...
  12. S

    The set consisting of random numbers with random lengths

    Does the set of random integers with random lengths (the number of digits), which hypothetically would generate random numbers with random lengths for eternity, produce all possible integers? It seems to me that this is a natural conclusion but I've never seen a proof of this. A more incredible...
  13. EinsteinKreuz

    Tricomplex numbers (Trinions anyone?)

    So what am I talking about? An extension of the complex numbers between ℂ1 and the Quaternions. A tricomplex number can be written as τ = {a + bi + cj | ∀(a,b,c)∈ℝ } where: i2 = j2 = i×j = -1 = -(j×i) Thus of course, j×i = +1 What is remarkable is that such objects are closed under...
  14. T

    MHB Prime numbers proof by contradiction

    For prime numbers, $a$, $b$, $c$, $a^2 + b^2 \ne c^2$. Prove this by contradiction. So, I get that $a^2 = c^2 - b^2 = (c - b)(c +b)$ And I get that prime numbers are the product of 2 numbers that are either greater than one, or less than the prime numbers. But I'm unsure how to go from here.
  15. N

    Forced Oscillation with complex numbers

    Homework Statement If a force F = F_0 cos (\omega t) = \Re{\{F_0 e^{i \omega t}\}} is applied to a body of mass m attached to a spring of constant k, and x = \Re\{z\} . Show that the following equation holds: m \ddot{z} = - k z + Fe^{i \omega t} . Homework Equations Newton's second law. The...
  16. P

    Sum the even numbers between 1000 and 2000 inclusive

    this is just an arithmetic series but with a small difference. i will show that below The attempt at a solution the general arithmetic formula ## S_N=\sum_{n=1}^\infty n## for my problem ## S_N=\sum_{n=1000}^{2000} n ## i have to rewrite it so i will just add the even numbers ##...
  17. LarryS

    Complex numbers sometimes *Required* in Classical Physics?

    In general, one thinks of complex numbers as being absolutely required in Quantum Physics but as being optional in Classical Physics. But what about modern classical electromagnetic field theory (gauge theory) in which the electromagnetic field is coupled to the field of charged particles by...
  18. R

    Comp Sci C++ Sum of prime numbers in matrix

    Homework Statement My Program is not showing the sum value or not returning it. A blank space is coming.Why that is so? Homework Equations Showing the attempt below in form of code. The Attempt at a Solution #include<iostream.h> #include<conio.h> Prime_Sum(int arr[30][30],int m, int n); void...
  19. N

    Is This Simple Algorithm the Key to Finding the Next Largest Prime Number?

    I have a simple algorithm that appears to generate many primes (or semi-primes with relatively large factors). By 'relatively large', I mean large in relation to inputs. I have tested this algorithm for small values, and of the forty (six-digit) numbers produced, 22 are prime, 16 are...
  20. M

    Negative numbers anomaly? And i?

    So, I'm to understand that "0 - -a = a" and I can understand this, in the context of say, being at an arbitrary reference point called "0" and then on a 2 dimension Cartesian graph of + shape and the operator "-", which can mean to reverse (so turn around 180 degrees) and then the second minus...
  21. C

    How to Solve Equations with Complex Numbers

    I have to solve the following equation: z4=i*(z-2i)4 Now, i tried to move everything but i (imaginary number) to the left side and then find the 4-th root of i, when i did that, i had four solutions, with one of them being eiπ/8. But i don't know what to do with the left side, since i get way...
  22. Vinay080

    Motivation for geometrical representation of Complex numbers

    I am seeing in "slow motion" the development of vectorial system. I am reading the book "A History of Vector Analysis" (by Michael J.Crowe); it seems from my acquaintance that the vector concept came from the quaternions concept; and the quaternions concept came from the act of search for...
  23. T

    Proof of |2^N x 2^N| = |2^N| with N the natural numbers

    Hello, At my exam I had to proof the title of this topic. I now know that it can easily be done by making a bijection between the two, but I still want to know why I didn't receive any points for my answer, or better stated, if there is still a way to proof the statement from my work. My work...
  24. Chrono G. Xay

    Predict Digits of Irrational Numbers with Modular Arithmetic Summation?

    Would it be possible to write an equation utilizing a summation of a modular function of a Cartesian function, whose degree is dependent upon the index of the root, in that it predicts the digits less than 1 of the root, that when summed equals the computed value sqrt( n )? I already have what...
  25. N

    Prime Numbers Between Two Quadratics: A Useful Result?

    Would it be a useful result to know there is at least one prime between 16x^2+4x-1 and 16x^2+8x-5 for any odd natural number x?
  26. R

    A philosophical question regarding random numbers....

    A number can be random even if limitations are applied to the outcome - e.g. selecting a random integer between 1 and 5 restricts the outcome to one of 5 numbers, but the outcome is still random. The same would be true of between 1 and 2; although there are heavy restrictions, an unbiased...
  27. P

    Understanding the Closed Set of Natural Numbers

    Hi, How and why set of natural numbers is closed?
  28. astrololo

    Proof of Complex Conjugates and Real Coefficients | Complex Numbers Homework

    Homework Statement I have two complex numbers that are non real, k and z. K and z are going to be complex conjugates if and only if the product (x-k)(x-z) is a polynomial with real coefficients. Here is my answer : k=a+bi z=c+di (x-k)(x-z) = x^2 -(k+z)x+kz Homework EquationsThe Attempt at...
  29. T

    Find Nice Numbers: A Program to Count Divisible Digits in Range [0,1000]

    Hello, My task is to write a program that after reading a positive integer i (from 0 to 1000) will write how many "nice numbers" are in the interval [0..i]. "Nice numbers" are numbers that are divisible by their every digit. For example 612 is a nice number becasuse it is divisible by 6,1 and 2...
  30. Einstein's Cat

    How Do Complex Numbers Affect Ket Vectors in Quantum Mechanics?

    In Dirac's "The Principles of Quantum Mechanics," ket vectors are multipled by complex numbers (c1 |A> + c2 |A> = c1 + c2 |A>) and I was curious what affect this has a) on the ket vector and b) on the entire system? Also is (c1 |A> + c2 |A> = c1 + c2 |A>) equal to (|A> + |A> = |A>)? Thank you...
  31. S

    How to show if a given array of numbers is a vector?

    Homework Statement I'm reading Zee's book Einstein Gravity, I'm in the section where he said that given an array of two numbers p=(ap1, bp2), it is not a vector unless a=b. He just stated it without really showing how it must be like that. I know that a vector should satisfy a transformation...
  32. T

    Complex numbers and physical meaning

    I have to say that I am a bit confused with the use of complex numbers. I know that: 1. They have been created by mathematicians to solve the "real"ly unsolved equation of x^2=-1. 2. They are used in many aspects of physics, like waves and quantum theory, with terrific correspondence to the...
  33. Den Webi

    A link from complex number to hypercomplex numbers

    If i understand correctly, the discovery of complex numbers was linked to solving real number problems, s.a. finding square roots of negative numbers. In other words, at first there was a problem that was formulated using real numbers only that had no real number solutions, which lead to...
  34. a1call

    A Is there a formula for generating prime numbers and proving their primality?

    I have figured out a formula that generates prime numbers along with the proof that all such generated numbers are primes. The way it works is that you have to input consecutive prime numbers staring from 2 and ending at some Pn. And no it's not primorial minus or plus 1. Is this of any value...
  35. astrololo

    Why do we need the set of complex numbers to solve?

    I was wondering, why is the set of complex numbers needed to solve problems that the set of reals doesn't permit to ? I mean, in relation to the fundamental theorem of algebra, that is.
  36. D

    Complex numbers and polynomial

    Homework Statement Hi,I have a problem regarding to one of the questions in my homework.Actually I am not trying to ask for the solution.I am just not sure what the question is asking for.Please see the attachedHomework EquationsThe Attempt at a Solution In 5(c),the summation notation stated...
  37. Calpalned

    Physical applications of complex numbers

    Homework Statement Homework Equations see picture above The Attempt at a Solution I can follow most of the steps, but not all. I got confused with finding ##|\frac{dz}{dt}|##. It is easy to derive ##\frac{dz}{dt}## from ##z##. Normally, I would square the two components of ##dz/dt## and...
  38. Calpalned

    A question about complex numbers

    Homework Statement I don't understand example 2. For part a, I got a slightly different answer. Homework Equations see picture The Attempt at a Solution ##|z-1|=2=\sqrt{x^2+y^2-1}## ##4=x^2+y^2-1 \neq (x-1)^2+y^2##
  39. thegirl

    Cross product imaginary numbers

    Hi, I was just wondering if you have a cross product can you multiply out the constants and put them to one side. So ik x ik x E is equal to i^2(k x k x E) therefore is equal to -k x k x E. Is that correct?
  40. D

    Arbitrary array of numbers, proof

    Homework Statement The numbers 1 to 25 are arranged in a square array of five rows and five columns in an arbitrary way. The greatest number in each row is determined, and then the least number of these five is taken; call that number s. Next, the least number in each column is determined, and...
  41. phion

    Colored Words or Numbers in VB6

    Hi, I've written some code in VB6, and I'm trying to figure out how to add color to individual words and numbers. The program is a console application Roulette game. What I need to figure out is how to make my money green if positive and red if negative, and color the words "red" and "black"...
  42. L

    Complex numbers - I'm sure this is an easy - Argand diagram

    Homework Statement OABC is a square on an Argand diagram. O Represents 0, A represents -4 + 2i, B Represents z, C represents w and D is the point where the diagonals of the square meet. (There are two possible squares that meet this criteria) Find the complex number represented by C and D in...
  43. S

    MHB Complex numbers and conjugates

    Hi everyone, Can you please assist with the following problem? The complex numbers z and w are such that for the real variable x, (x-z)(x-w)=ax2+bx+c for real a,b and c. By letting z=p+qi and w=r+si, prove that z and w must be conjugates of one another.So far, I have determined that a=1...
  44. J

    Proving that the natural numbers are countable, stuck.

    Homework Statement [/B] I'm working through a problem in Abott's Understanding Analysis, second edition, the statement of the problem being: "Fix a member n of the natural numbers and let An be the algebraic numbers obtained as roots of polynomials with integer coefficients that have degree n...
  45. N

    Why my synchronous counter toggling between two numbers?

    EDIT: SOLVED I designed a bi-directional synchronous counter with the sequence 7 4 6 5 2 1. The up count counts correctly (ie 7 4 6 5 2 1) but when I flick the switch to reverse it it counts backwards correctly initially until it reaches 5, and then it goes back to 2 and then back to 5 and...
  46. R

    Engineering Combinational circuit that multiplies two numbers together

    Homework Statement Design a combinational circuit that multiplies two numbers together, and outputs the result. Homework Equations The biggest product will be 3 * 3 = 9. Four bits to represent the product. 0: 00 1: 01 2: 10 3: 11 I need a 4 bit register for the outputs The Attempt at a...
  47. Gjmdp

    Why Nitrogen has 5 Oxidation Numbers that are false?

    My Chemistry Teacher told that 5 of the 6 oxidation numbers of Nitrogen are not true. He said something like it is a mathematical trick for I don't know what. The real oxidation number is -3. Can anyone explain me what are the 5 false oxidation number? Thank you.
  48. micromass

    Insights Informal Introduction to Cardinal Numbers - Comments

    micromass submitted a new PF Insights post Informal Introduction to Cardinal Numbers Continue reading the Original PF Insights Post.
  49. R

    How to Write Canceled Numbers in Word 2010?

    Hello, I want to know how to write the canceled numbers in a fraction using Microsoft Word 2010. Please see the attached image. Thank you.
  50. K

    Are there prime numbers n for which S=/0?

    We have the set:S={1<a<n:gcd(a,n)=1,a^(n-1)=/1(modn)} Are there prime numbers n for which S=/0?After this, are there any composite numbers n for which S=0? (with =/ i mean the 'not equal' and '0' is the empty set) for the first one i know that there are no n prime numbers suh that S to be not...
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