Numbers Definition and 1000 Threads

  1. I

    MHB Can we simplify calculating large sums of numbers?

    uhh, how would we get a better way?
  2. A

    MHB Finding 3 natural numbers by the rule of Sarrus

    Here is a problem I am working on: Using the Rule of Sarrus: $$\begin{vmatrix} x & y & z \\ z & x & y \\ y & z & x \\ \end{vmatrix} =x^3+y^3+z^3-3xyz,$$ find $x, y, z$ such that $x^3+y^3+z^3-3xyz = 315.$ And here is what I have gotten so far: By row and column operations and by factoring out...
  3. anemone

    MHB What are the real numbers a, b, and c that satisfy certain conditions?

    Determine all three real numbers $a, \,b$ and $c$ which satisfies the conditions $a^2+ b^2+ c^2= 26$, $a + b = 5$ and $b + c\ge 7.$
  4. M

    MATLAB MATLAB extract numbers in .txt file

    Hi PF! I have a .txt file with spaces and letters, along with numbers. It looks something like this: 12.0 42.0 21.0 32.0 ICF-8-1 23.0 24.0 46.0 600.0 Additionally, the first two sets of numbers each represent a coordinate pair. Then the first coordinate is (12,42) and the second is...
  5. whatphysics

    How do you work out simultaneous eqns w/ complex numbers & phasor

    I'm having trouble figuring out to get the answers from the 2 equations. The phasors and complex numbers confuse me. Do I need to change the phasor form? How do I go about doing this thanks! (Not homework question I am trying to figure this for my exam!)
  6. parshyaa

    B Why negative numbers inside root can't be separated?

    Why √[(-a).(-b)] can't be written as √(-a).√(-b) Is it only because complex number do not work for this statement. Just like here: √ab = √[(-a).(-b)] = √a√bi^2 = -√ab which is wrong. We can separate √(-4)(9) = √-36 = 6i , √4i.√9 =6i, but why can't we separate for two negative numbers inside...
  7. S

    I Quantum numbers of Landau levels

    I have been reading about Landau levels for a two-dimensional system of charged particles in a perpendicular magnetic field and I have trouble understanding why there is degeneracy in the system. Let me provide some background to my problem. In the presence of a magnetic field, the momentum of a...
  8. M

    I What does N^2 mean in the case of natural numbers?

    What does the N^2 mean in this case? (Image below) Does it mean, for all two pairs of natural numbers, a and b? How would I represent non pair numbers, i.e. how would I write "For integers k,l, and m such that k>1, l>2, m>k+l" all in one line?
  9. A

    Java Java: Finding the numbers in an array above the average

    I am attempting to find the numbers above the average number of a set of numbers in an array. I am having trouble understanding why my output for the list of numbers above the average is so...weird. I'd appreciate the help! My code: public class Inequality { public static void main(String[]...
  10. kaliprasad

    MHB Showcase of 2016 Consecutive Numbers w/ 100 Primes

    Show that there exists 2016 consecutive numbers that contains exactly 100 primes.
  11. shina

    What is the formula for adding a sequence of consecutive numbers?

    Homework Statement Homework EquationsThe Attempt at a Solution hey hello every one I want to ask a question that is add 1+2+3+4.....10000000. I think its very easy. for example let us add first 5 numbers 1+2+3+4+5 now we can find a pattern that adding first and last digit will be always same...
  12. L

    A Why the Chern numbers (integral of Chern class) are integers?

    I am a physics student trying to self-learn Chern numbers and Chern class. The book I am learning (Nakahara) introduces the total Chern class as an invariant polynomial of local curvature form ##F## ## P(F) = \det (I + t\frac{{iF}}{{2\pi }}) = \sum\limits_{r = 0}^k {{t^r}{P_r}(F)} ## and each...
  13. MickeyBlue

    I Sketching Complex Numbers in the Complex Plane

    I've just had my first batch of lectures on complex numbers (a very new idea to me). Algebraic operations and the idea behind conjugates are straightforward enough, as these seem to boil down to vectors. My problem is sketching. I have trouble defining the real and imaginary parts, and I don't...
  14. M

    MHB Add Up Numbers: Get to 21 or Stop at 0

    Ask the user for a number between 1 and 11; stop asking when the user enters 0 OR when the total goes over 21. Display the total on the screen. For example: #include<iostream> #include<cmath> using namespace std; int main(){ int num, total; cout << "Enter a number between 1 and 11...
  15. Albert1

    MHB Find the total numbers to make A=21

    $A=$$\square$1 $\square$2 $\square$3$\square$4 $\square$5$\square$6 $\square$7 $\square$8 $\square$9 randomly fill in each blank with eather $"+"$ or $"-"$ , (1) prove $A$ can not be $12$ (2) find the total numbers to make $A=21$
  16. nysnacc

    Suppose a, b, c are three real numbers such that

    Homework Statement Homework Equations character equation The Attempt at a Solution Should I set a = ax2 b= bx c =c in the character equation?
  17. PsychonautQQ

    Deducing [Field of Algebraic Numbers : Q] is infinite

    Homework Statement Use Eisenstein's criterion to show that there exists irreducible polynomials over Q or arbitrarily large degree, and from this deduce that the field of algebraic numbers is an infinite extension of Q Homework Equations none The Attempt at a Solution Note that x^n+4x+2 is...
  18. A

    B What are surreal numbers and how do they work?

    Hey guys! I have heard of this concept in various places and sort of understands what it attempts to do. Can anybody please explain it to me in more detail like how it works, how to notate it, and how to expand it to infinities and infinitesimals. Thanks in advance! Aakash Lakshmanan xphysx.com...
  19. A

    Finding Real Numbers: Questions (c) & (e) Solutions

    Homework Statement Please see questions (c) and (e) on the attachement 2.Relevant Equations The Attempt at a Solution So long story short, these two questions were given out as a challenge in one of our Swedish lessons to see if we could remember our high school calculus, which I shamefully...
  20. F

    B Why Is the Distance Between Two Real Numbers Given by Their Absolute Difference?

    Why is it that the distance between two real numbers ##a## and ##b## in an ordered interval of numbers, for example ##a<x_{1}<\ldots <x_{n-1}<b##, is given by $$\lvert a-b\rvert$$ when there are in actual fact $$\lvert a-b\rvert +1$$ numbers within this range?! Is it simply that, when measuring...
  21. throneoo

    I (Index Notation) Summing a product of 3 numbers

    I have just begun reading about Einstein's summation convention and it got me thinking.. Is it possible to represent ∑aibici with index notation? Since we are only restricted to use an index twice at most I don't think it's possible to construct it using the standard tensors (Levi Cevita and...
  22. Ling Min Hao

    Number Theory Is Introduction to Theory of Numbers by Hardy good ?

    I am currently an undergraduate students at university and i am keen on learning some mathematics that is not taught in school and i have chosen number theory as my main topic . Recently I have picked number theory by Hardy but I found it is quite hard to understand sometimes as I have quite a...
  23. M

    I Cancellation law multiplication natural numbers

    Hello everyone. I wanted to prove the following theorem, using the axioms of Peano. Let ##a,b,c \in \mathbb{N}##. If ##ac = bc##, then ##a = b##. I thought, this was a pretty straightforward proof, but I think I might be doing something wrong. Proof: Let ##G := \{c \in \mathbb{N}|## if ##a,b...
  24. M

    I Simultaneous Solution for Two Modular Equations with Known Integers

    let equation 1: x % n1 = 0, equation 2: x % n2 =1, where n1 and n2 are known positive integers, any multiple of n1 will solve eqn1 and any multiple of n2 (and adding 1 to the multiple) will solve eqn2, but is there a short way to simultaneously solve the two equations to find x instead of...
  25. C

    What are the properties of nonzero complex numbers satisfying z^2 = i\bar{z}?

    Homework Statement Consider 3 nonzero complex numbers $$z_1,z_2,z_3$$ each satisfying $$z^2=i \bar{z}$$. We are supposed to find $$z_1+z_2+z_3, z_1z_2z_3, z_1z_2+z_2z_3+z_3z_1$$. The answers- 0, purely imaginary , purely real respectively. Homework EquationsThe Attempt at a Solution I have...
  26. M

    Can I solve this complex numbers equation? Finding values for z

    Homework Statement ask to find all the values in z to the equation to be true[/B]Homework Equations [/B]The Attempt at a Solution this is my atemp of solution i don't know what else do, because the problem ask for z values well i must add that i am thinking about x=0 and y= pi/2 will solve...
  27. P

    MHB Can Irrationals Be Matched One-to-One with Natural Numbers?

    Hi, New member here and have been dabbling with some aspects of George Cantor's work. I think I have found a way to put the irrationals in one to one correspondence with natural numbers but thousands of mathematicians over the years might disagree. Is there a subtle error ( or even a blatant...
  28. terhje

    Complex numbers. write equation on form "a+bi"

    Homework Statement Write this complex number in the form "a+bi" a) cos(-pi/3) + i*sin(-pi/3) b) 2√2(cos(-5pi/6)+i*sin(-5pi/6)) Homework Equations my only problem is that I am getting + instead of - on the cosinus side.(real number) The Attempt at a Solution a) pi/3 in the unit circle is 1/2...
  29. Marcin H

    Complex Numbers (Exponential/Rectangular Form)

    Homework Statement Homework Equations Theta = arctan (y/x) The Attempt at a Solution Hopefully this is the right section to post in, but I am a bit confused with complex numbers. I am working on the problems above and I just wanted to make sure I am doing each part correctly. I think A...
  30. H

    B Connections with Prime numbers and Quantum Physics?

    Hello I'm hard at work trying to find a pattern for the prime numbers and this keeps cropping up. To be honest though, to me it comes across like pseudo science. I mean I never really hear people talk about it. This seems an obvious thing to look into but I don't know anyone who does. Prime...
  31. L

    A Why Can't the Continuum Hypothesis Be Decided Using Standard Real Number Models?

    I know that there are several models of the real numbers, some where the Continuum Hypothesis holds, others where it does not. I would like to understand why the usual definition of the reals, limits of Cauchy sequences of rational numbers under the usual absolute value norm, isn't one of these...
  32. M

    A If the axiom of induction were extended to include imaginary numbers....

    If the axiom of induction was extended to include imaginary numbers, what effect would this have? The axiom of induction currently only applies to integers. If this axiom and/or the well ordering principle was extended to include imaginary numbers, would this cause any currently true statements...
  33. L

    MHB Complex numbers simultaneous equations

    Hi all, I have spent a couple of hours on this perplexing question. Solve the simultaneous equations: z = w + 3i + 2 and z2 - iw + 5 - 2i = 0 giving z and w in the form (x + yi) where x and y are real. I tried various methods, all to no avail. I have substituted z into z2 , I got the wrong...
  34. F

    What properties do prime numbers exhibit?

    Mod note: moved from a homework section What properties do prime numbers exhibit which can be used in proofs to define them? Like rational numbers have a unique property that they can be expressed as a quotient of a/b. Even numbers have a unique property of divisibility by 2 and thus they can be...
  35. evinda

    MHB How is binary addition performed?

    Hello! (Wave) According to some notes of computability theory: Addition of binary numbers $$10011\\ +11111 \\ ------ \\ 110010$$ I haven't understood how they do the addition, since it holds that $1+1=0$... (Sweating) Could you explain it to me?
  36. Rectifier

    What Are the Roots of the Equation ##z^4-2z^3+12z^2-14z+35=0##?

    The problem The following equation ##z^4-2z^3+12z^2-14z+35=0## has a root with the real component = 1. What are the other solutions? The attempt This means that solutions are ##z = 1 \pm bi##and the factors are ##(z-(1-bi))(z-(1+bi)) ## and thus ## (z-(1-bi))(z-(1+bi)) =...
  37. DuckAmuck

    I Question about the gaps between prime numbers

    Is there any prime number pn, such that it has a relationship with the next prime number pn+1 p_{n+1} > p_{n}^2 If not, is there any proof saying a prime like this does not exist? I have the exact same question about this relation: p_{n+1} > 2p_{n}
  38. T

    B How Do You Compute the Expression E = AB - B^*A^* with Complex Numbers?

    If I have 2 complex numbers, A and B, what is the correct way to evaluate this expression: ## E = AB - B^*A^*## I was under the impression that when taking the product of complex numbers, you always conjugate one factor, but in this instance, it is quite important which one is conjugated, no...
  39. kaliprasad

    MHB Co-prime Numbers in a Series of 10

    Show that in 10 consecutive numbers there is at least one number which is co-prime to other 9 numbers.
  40. P

    MHB Question via email about complex numbers

    We should note that we can write any complex number as $\displaystyle \begin{align*} z = r\,\mathrm{e}^{\mathrm{i}\,\theta} \end{align*}$ where $\displaystyle \begin{align*} r = \left| z \right| \end{align*}$ and $\displaystyle \begin{align*} \theta = \textrm{arg}\,\left( z \right) + 2\,\pi\,n ...
  41. M

    MATLAB Too little appearance of symbols and numbers in matlab

    Hi, When I using Matlab 2008, the symbols and numbers were big enough to see but now I use Matlab 2013 but symbols and numbers or what I write is too little. How can I make them bigger? Thank you.
  42. T

    Python Adding very small values to very large numbers

    I am using complex numbers and was wondering if there's any way that I can get output to match my exact input when performing basic arithmetic on them. For example, if I use type = complex_ or complex256, with A = 1. and B = 6.626 x 10^(-34), then C = A*B yields C = 6.626 x 10^(-34) as wanted...
  43. P

    MHB Effie's question via email about Complex Numbers

    First let's write this number in its polar form. $\displaystyle \begin{align*} \left| z \right| &= \sqrt{\left( -2 \right) ^2 + 2^2} \\ &= \sqrt{4 + 4} \\ &= \sqrt{8} \\ &= 2\,\sqrt{2} \end{align*}$ and as the number is in Quadrant 2 $\displaystyle \begin{align*} \textrm{arg}\,\left( z...
  44. M

    MHB Surjectivity of x²+3 for Real Numbers: Testing for Surjectivity

    is the function x²+3 surjective for real numbers. how do you test for surjectivity in general?
  45. anemone

    MHB Comparison between two numbers

    Compare the numbers $2^{2016}$ and $3^{201}7^{604}$.
  46. zrek

    I Venn diagram for the reals and transfinite numbers as sets

    My statement: The first transfinite ordinal, omega is the first number that cannot be expressed by any natural number, therefore it is not included in the set of natural numbers. The set of natural numbers is a subset of real numbers, every natural number can be taken out of it, but still true...
  47. 7

    MHB Random picking of 3 digit numbers

    If the odds of randomly picking a 3 digit number correctly are 1000-1, then what are the odds of that same number being picked 4 times in 364 picks?
  48. Y

    L, m quantum numbers of 3D oscillator

    Homework Statement 6 degenerate energy states at E=7/2 h-bar w in isotropic 3D harmonic oscillator. pick one possible state( for example, (nx,ny,nz)=(1,0,1)), and find possible l, m quantum numbers you may use orthonormality of spherical harmonics[/B] Homework Equations pick one possible...
  49. chwala

    Complex numbers : quadratic equation

    Homework Statement Showing all necessary working solve the equation ##iz^2+2z-3i=0## giving your answer in the form ##x+iy## where x and y are real and exact,Homework EquationsThe Attempt at a Solution ##iz^2+2z-3i=0, z^2+(2/i)z-3=0##,using quadratic formula →##(-2/i± √8)/2 , z= √2+1/i## and...
  50. 5

    Complex numbers in the form a+bi

    Homework Statement How would I go about solving 1/z=(-4+4i) The answer that I keep on getting is wrong The Attempt at a Solution [/B] What I did z=1/(-4+4i)x(-4-4i)/(-4-4i) z=(-4-4i)/(16+16i-16i-16i^2) z=(-4-4i)/32 z=-1/8-i/8 This is the answer that I got however it says that it is...
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