Numbers Definition and 1000 Threads

  1. A

    Python Python program to sort negative numbers and even numbers?

    Homework Statement I have to make a program that would end when entered a 0 and print out negative numbers and even numbers separately but what I have so far is not working. The Attempt at a Solution numbers = [] negative_numbers = [] while True: number = input("Enter a number: ")...
  2. L

    Magic Numbers in the Nucleus: Fact vs. Fiction

    I am really not sure and do not understand how you find out what are the magic numbers in case of nucleus. Here in leson lecturer said that magic number is ##114##, and in other resourses I find number ##126##? Do we have any real confirmation of this?
  3. DiracPool

    Irrational numbers and Planck's constant

    [Mentor's note: this was originally posted in the Quantum Physics forum, so that is what "this section" means below.] ---------------------------------------------------- I wasn't sure whether to post this question in this section or the general math section, so I just decided to do it here...
  4. K

    MHB Showing that equality of complex numbers implies that they lie on the same ray

    This problem has been on my mind for a while. ---------- **Problem:** Show that **if** \begin{equation} |z_1+z_2+\dots+z_n| = |z_1| + |z_2| + \dots + |z_n| \end{equation} **then** $z_k/z_{\ell} \ge 0$ for any integers $k$ and $\ell$, $1 \leq k, \ell \leq n,$ for which $z_{\ell} \ne 0.$...
  5. D

    What is measure of numbers with certain property on [0,1]

    Considering the interval [0,1], say for each number (binary) on the interval you form the sequence of numbers: number of zeros up to the nth place/number of ones up to the nth place. Then as n goes to infinity the sequence of numbers (for the given binary number) will go to somewhere in...
  6. A

    Python Python checking numbers in a given name

    Homework Statement I need to write a Python program, which would: 1) Ask for a name (input function) 2) Keep asking for the name if it is not entered correctly(if it has a digit in it) 3) If the name is entered correctly it will print the name Homework Equations How should I continue the...
  7. K

    Prime Numbers as Ortho-normal basis for all numbers

    Hi, Can we treat prime numbers as an Ortho-normal basis of "Infinite" dimensions to represent every possible number. Treating numbers as vectors. Thanks.
  8. qpwimblik

    R-Simplex's the number 5 and prime numbers.

    So if you do a search for R-Simplexs you should find that. RSimplex(n,d)=Pochhammer(n,d)/d! Well so to does RSimplex(n,d)=If(n<d, Pochhammer(d+1,n-1)/n!, Pochhammer(n,d)/d!) Or something like that my maths package is down so I'm not sure quite how it works. Anyway the relationship between...
  9. Khronos

    Optimisation - Critical Numbers for Complex Functions.

    Hi everyone, I need a little bit of help with an optimization problem and finding the critical numbers. The question is a follows: Question: Between 0°C and 30°C, the volume V ( in cubic centimeters) of 1 kg of water at a temperature T is given approximately by the formula: V = 999.87 −...
  10. L

    Fortran [Fortran] Rounding up Random Numbers

    Hi, So I'm writing a programme in Fortran95 atm and I want to produce an array of 1s and 0s. I've used a random number and random seed generator to produce 10 numbers between 0 and 1 and I want to use a NINT statement to round these random numbers to 0 or 1. However when I try this the...
  11. N

    Can Complex Numbers Bridge the Gap Between Algebra and Geometry?

    This really isn't a homework question but I wasn't sure where to post it. I was watching a video by numberphile about complex numbers and the professer being interviewed said the most important thing about complex numbers is that they help bring algebra and geometry together. What did he mean by...
  12. W

    Sum of a geometric series of complex numbers

    Homework Statement Given an integer n and an angle θ let Sn(θ) = ∑(eikθ) from k=-n to k=n And show that this sum = sinα / sinβ Homework Equations Sum from 0 to n of xk is (xk+1-1)/(x-1) The Attempt at a Solution The series can be rewritten by taking out a factor of e-iθ as e-iθ∑(eiθ)k from...
  13. STEMucator

    Multiplying two's complement numbers

    Homework Statement I'm a little confused by the wiki article, and I can't seem to get the correct answer. Suppose ##A = 01100101 = +101## is an 8-bit two's complement number. I'm trying to multiply ##A \times 101 = 01100101 \times 101 = (+101) \times (-3) = -303##. Homework EquationsThe...
  14. M

    Engineering Detector of even numbers in logic circuit

    Homework Statement I need to make a circuit that detects even numbers. Need to find the equation for F when input A and B are both even. Input A: Word of 5 -bit signed representation in complement 2. Input B: Word of 3 -bit signed representation in complement 2. Homework Equations for B...
  15. E

    What are the important numbers in Cosmology?

    What are the important numbers in cosmology that dictates the very fate of the universe? I searched through Google and one site states that they are 13 constants; http://www.popularmechanics.com/flight/g163/13-most-important-numbers-in-the-universe/ What could be the possible consequences if...
  16. HiggsBoson1

    Understanding Quantum Numbers: Exploring Half Integers and Their Limitations

    I don't understand why quantum numbers can not be divided into half integers and so on. The books I have read do not give clear explanations. Would anyone mind helping me understand this? Thanks!
  17. C

    Comparing 2-Bit Numbers with a Single Decoder and Standard Logic Gates

    < Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Is there a way to create two bit numbers comparator using one 2 to 4 decoder and standard logic gates?
  18. mukul

    Do low atomic numbers not obey Moseley's law?

    Helium has k-alpha of 24.5 eV whereas if we derive it using Moseley's law, then it is supposed to be 10.2 eV Also I then looked into many sources and found that Moseley's graph talks about elements having z>=10 only Later I found in few sources that the assumption that "one electron shields...
  19. M

    Question regarding complex numbers

    1)If a= cosα + i sinα and the equation az2 + az +1 =0 has a pure imaginary root, then tanα=? 2) cosα+isinα=eiα , quadratic formula 3) What i tried to do was,i put a constant real number and tried to solve it and used demoivres theorem, although the answer is getting weirder and weirder.
  20. Ahmad Kishki

    Linear Algebra Linear algebra with complex numbers

    Recommend a self study book for linear algebra with complex numbers
  21. E

    Closed/Open Sets and Natural Numbers

    Homework Statement I am trying to understand why ℕ the set of natural numbers is considered a Closed Set. 2. Relevant definition A Set S in Rm is closed iff its complement, Sc = Rm - S is open. The Attempt at a Solution I believe I understand why it is not an Open Set: Given that it...
  22. H

    Principle and Angular Momentum Quantum Numbers

    My understanding of the angular momentum quantum number is that a different number indicates a different region of space that the electron can occupy. So does the principle quantum number determine the size of that region? For example, is 2s the same as 3s in shape, but the 3s has a greater...
  23. X

    MHB Solving 6-dimensional Equations | Find Unknown Numbers

    How can the six unknown numbers be derived by constant letters of 6-dimensional equations?
  24. nmsurobert

    Partial derivatives and complex numbers

    Homework Statement show that the following functions are differentiable everywhere and then also find f'(z) and f''(z). (a) f(z) = iz + 2 so f(z) = ix -y +2 then u(x,y) = 2-y, v(x,y) = x Homework Equations z=x+iy z=u(x,y) +iv(x,y) Cauchy-Riemann conditions says is differentiable everywhere...
  25. Logan Land

    Expressing complex numbers in the x + iy form

    Homework Statement ((1-i)/(sqrt2))^42 express in x+iy form Homework Equations z1/z1=(r1/r2)e^(i(theta1-theta2)) The Attempt at a Solution Ive found that (1-i) has r=sqrt2 so since r is sqrt2 and x=1 y=-1 so the angle is 7pi/4 so then I have (sqrt2e^(-i7pi/4)/sqrt2)^42 now from here is where I...
  26. G

    Linking Fourier Transform, Vectors and Complex Numbers

    Homework Statement Homework EquationsThe Attempt at a Solution I tried to attempt the question but I am not sure how to start it, at least for part (i). My biggest question, I think, is how does the multiplication of a random complex number to a Fourier-Transformed signal (V(f)) have an...
  27. B

    Symbol in Alan Turing's On Computable Numbers

    In Alan Turing's On Computable Numbers, he explains in his second paragraph the general notion of computable numbers. In doing so, he writes "In [symbol][symbol] 9, 10 I give some arguments...". I will include a screenshot of these symbols in this post. Do any of you know what these symbols...
  28. anemone

    MHB Proving Inequality with Positive Real Numbers $x,\,y,\,z$

    Let $x,\,y,\,z$ be positive real numbers such that $xy+yz+zx=3$. Prove the inequality $(x^3-x+5)(y^5-y^3+5)(z^7-z^5+5)\ge 125$.
  29. evinda

    MHB Can Cardinal Arithmetic Mimic Distributive Property?

    Hi! (Nerd) I want to prove for any cardinal numbers $m,n,p$ it holds that: $$m \cdot (n+p)=m \cdot n+m \cdot p$$ Could we prove this using induction on m ? Or could we maybe show that $A \times (B \cup C)=(A \times B) \cup (A \times C)$ where $card(A)=m, card(B)=n, card(C)=p$ ? (Thinking)
  30. M

    Sum of n consecutive numbers is divisible by n

    I'm trying to investigate this statement: The sum of n consecutive numbers is always divisible by n. I've found already that it's only true when the total amount of numbers is an odd number. I've also found that the median and mean are the same with consecutive numbers. I can not prove that the...
  31. Math Amateur

    MHB Every interval (a,b) contains both rational and irrational numbers

    I am reading Chapter 1:"Real Numbers" of Charles Chapman Pugh's book "Real Mathematical Analysis. I need help with the proof of Theorem 7 on pages 19-20. Theorem 7 (Chapter 1) reads as follows: In the above proof, Pugh writes: " ... ... The fact that a \lt b implies the set B \ A contains...
  32. evinda

    MHB Each subset of the natural numbers is finite or countable

    Hello! (Smile) Proposition: Each subset of the natural numbers is finite or countable. Proof: Let $X \subset \omega$. First case: $X$ is bounded. That means that $(\exists k \in \omega)(\forall y \in X) y \leq k$. Then $X \subset k+1$ and $X$, as a subset of a finite subset, is finite ...
  33. collinsmark

    Radiolab's "Numbers" Podcast: Exploring How Numbers Affect our Lives

    Radiolab is a radio show broadcast on public radio stations across the United States. This week's Radiolab was titled Numbers. This Numbers podcast discusses how numbers affect our daily lives, how infants intuitively perceive numbers (logarithmically), and how children eventually learn to...
  34. evinda

    MHB What is the definition of real numbers in terms of rational sequences?

    Hi! (Smile) We define the set $U=\mathbb{Z} \times (\mathbb{Z}-\{0\})$ and over $U$ we define the following relation $S$: $$\langle i,j \rangle S \langle k,l \rangle \iff i \cdot l=j \cdot k$$ $$\mathbb{Q}=U/S=\{ [\langle i, j \rangle ]_S: i \in \mathbb{Z}, j \in \mathbb{Z} \setminus \{0\}...
  35. A

    How many numbers that are multiples of 5 divide 1000?

    Homework Statement Okay: How many numbers divide 1000 that are multiples of 5 I have seen you do 1000/5 = 200 But how does this mean there are 200 numbers that divide 1000 that are multiples of 5? This just says: 1000 divided into 5 equal pieces, is 200. So how does this give how many...
  36. evinda

    MHB Can Recursion Define Natural Number Addition?

    Hello! (Wave) For each pair of natural numbers $m \in \omega, n \in \omega$ we define: $$m+0=m\\m+n'=(m+n)'$$ We fix a $m$ and recursively the operation $m+n$ is defined for any $n \in \omega$. Knowing for example that $m+0=m$ we can conclude what $m+1$ means. $$m+1=m+0'=(m+0)'=m'$$ and...
  37. neosoul

    Complex numbers and differential equations for physics

    How relevant is complex analysis to physics? I really want to take differential equations but I would have to change my schedule around way more than I want to. So, would anyone advise a physics major to to take complex analysis? Should I just change my schedule around so I can take differential...
  38. P

    Why were complex numbers introduced in physics?

    hello can you tell me please why we introduced complex numbers? what was the problem that we couldn't express with rest of algebra and we introduced complex numbers? I am basically interested in why we introduced complex number to describe and analyze AC circuits, like voltage, current and...
  39. M

    Understanding the Solution for Finding the Sum of Digits of m

    Homework Statement Let m be the number of numbers fromantic the set {1,2,3,...,2014} which can be expressed as difference of squares of two non negative integers. The sum of the digits of m is ... Homework EquationsThe Attempt at a Solution I got a solution from a magazine but I didn't under...
  40. evinda

    MHB Prove Natural Numbers Subset Property

    Hello! (Wave) I want to prove that for any natural numbers $n,m$ it holds that: $$n \subset m \leftrightarrow n \in m \lor n=m$$ $"\Leftarrow"$: Using the sentence: "For any natural numbers $m,n$ it holds that $n \in m \rightarrow n \subset m$" if $n \in m \lor n=m$, we conclude that $n...
  41. Elroy

    Qubits, 2 complex numbers, forcing one to real

    Hi All, I'm working out a program to emulate a quantum computer (definitely in a nascent stage), and I'm struggling with a piece of the math. I looked at the math sections in these forums, but thought this might be more appropriate to post it. I'll try to conceptually outline the problem, and...
  42. T

    Learning General Relativity: Finding Examples with Numbers

    I am currently learning general relativity and I kind of understand what the symbols in einstein field equationd represent. But I need example like those that involves actual numerical values. I have been trying to search for it online but I cant. So does anyone mind showing me how you apply...
  43. E

    Rotation formula Complex numbers

    Homework Statement If arg(\frac{z-ω}{z-ω^2}) = 0, \ then\ prove \ that\ Re(z) = -1/2 Homework Equations ω and ω^2 are non-real cube roots of unity. The Attempt at a Solution arg(z-ω) = arg(z-ω^2) So, z-ω = k(z-w^2) Beyond that, I'm not sure how to proceed. Using the rotation formula may also...
  44. G

    Feynman rules - where do the imaginary numbers come from?

    I'm trying to learn how to derive Feynman rules (what else to do during xmas, lol). The book I'm using is QFT 2nd ed by Mandl&Shaw. On p 428 they're trying to show how to derive a Feynman rule for W W^\dagger Z^2 interaction term g^2 \cos^2\theta_W\left[W_\alpha W_\beta^\dagger Z^\alpha Z^\beta...
  45. P

    MHB Determining the Median of Five Median Numbers

    Problem: My goal is to show the median income among five different groups of people, where the median income for each group has already been determined. Is it as simple as choosing the median income of $ 45,615 since there are five numbers? Here is the information: Group One's Median Income...
  46. B

    Multiplying numbers from One set with another set

    Homework Statement Bob makes two sets: one with all the even integers between 1 and 30 inclusive, and another with all the odd integers inclusive. He called the sets Q and R. He multiplied each number from Q with each number in R. Then he added the 225 products together and called the result...
  47. L

    What makes complex numbers so special?

    Is there in a nutshell an explanation or even a single reason why complex numbers have so many fascinating consequences and give rise to so much deep stuff like analytic functions (with all its stunning properties), Riemann surfaces, analytic continuations, modular forms, zeta function, its...
  48. P

    Why is the principal square root of a complex number not well-defined?

    Within the context of real numbers, the square root function is well-defined; that is, the function ##f## defined by: ##f(x) = \sqrt{x}## Refers to the principal root of any real number x. Is it true that this is not the case when dealing with complex numbers? Does ##\sqrt{z}##, where ##z ∈ ℂ##...
  49. J

    What is the easiest method for adding and subtracting rational numbers

    What is the easiest method for adding and subtracting rational numbers
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