Integer Definition and 606 Threads

  1. T

    Number Theory least divisor of integer is prime number if integer is not prime

    Homework Statement The question is not really a question from a book but rather a statement that it makes : it says " Obviously the least divisor[excluding 1] of an integer a is prime if a itself is not prime." I kind of believe this statement but I'm having trouble proving the general case...
  2. S

    Least positive integer, modular problem HELP

    Homework Statement find the least positive integer n for which 5^{n} \equiv 1 (mod17) or 5^{n} \equiv -1 (mod 17) Homework Equations The Attempt at a Solution I really don't understand and method to doing these problems as I can't use a calculator and I can only work out...
  3. G

    Find the integer that is nearest to the area of complex plane A

    Consider the region A in the complex plane that consists of all points z such that both \frac{z}{40} and \frac{40}{\overline{z}} have real and imaginary parts between 0 and 1, inclusive. What is the integer that is nearest the area of A? Let z = a + bi and \overline{z} = a - bi a = real part...
  4. S

    Fortran Converting integer data to string in fortran 90

    hi all, i have the following code: do n = ninit,nlast character(len=20) :: filename integer :: n do n = 1,600 write (filename, "I0") n open (unit=110,file='wave'//trim(filename)//'.dat',action = 'write',status = 'old') do i = iinit+1,ilast-1 !boundary condition...
  5. C

    Probability of 2 equivalent random selections from integer sets

    What is the probability that a number selected from 0-9 will be the same number as one randomly selected from 0-4? Relevant equations: $$P(A \cap B) = P(A)*P(B|A)$$ I used the equation above, using A as the event that the number selected from 0-9 will be between 0 and 4, and B as the event that...
  6. P

    The Requirement of integer orbitals

    If there is a cloud of electrons around an atom than why can't there be orbitals between 1 and 2 or between 2 and 3. I know the probability of an electron being between certain nodes decreases as they approach them but why as the probabilities go away from the perfect orbital do they not become...
  7. R

    Why isn't this a machine sized integer

    In:list5 = Import["Composites.csv"]; (*imports a list of odd integers each less than 1000000*) Timing[f=Compile[{{Caa,_Integer},{S0,_Integer},{S1,_Integer},{Co,_Integer}}, Module[{xCo=Co,xS0=S0,xS1=S1,Temp},While[Temp=Mod[6 xS1-xS0-6,Caa];xCo>0&&Temp>=1, xS0=xS1;xS1=Temp;xCo--]; xCo]]...
  8. F

    Sub-quotients and Gaussian Integer rings

    This has to do with number theory along with group and set theory, but the main focus of the proof is number theory, so forgive me if I'm in the wrong place. I've been struggling to understand a piece of a proof put forth in my book. I know what the Gaussian integers are exactly, and what a...
  9. R

    Signed long integer overflow detection in C

    Hi, I have three situations where might be overflow is occurring. I need to write test cases to resolve this problem. I don't know how to continue after this, please anyone have suggestions to overcome this. Please help me.
  10. S

    What is the number of significant digits in a integer with trailing 0's ?

    It seems that there is a possible ambiguity in the number of significant digits if there are trailing 0's, but no decimal point or overline or underline. Specifically, I am looking at the definition of the second, which the Halliday & Resnick book has listed as 9 192 631 770 So is this 9...
  11. L

    Prove that x is irrational unless it is an integer.

    Homework Statement This is taken from an answer book that I have. I don't understand the bolded step. Can someone explain it to me?Suppose x = p/q where p and q are natural numbers with no common factor. Then: pn/qn + an-1pn-1/qn-1 + ... + ao = 0 and multiplying both sides by...
  12. S

    Mathematica Mathematica: Multiplicative Inverse of an integer using modulo

    Hello everyone, I've been trying to figure out how to obtain the multiplicative inverse of an integer in Zn in Mathematica but I haven't found a way. Is there a way to do this anyone can help me with?
  13. D

    Is Every Square Integer of the Form 4n or 4n+1?

    I want to prove that the square of any integer is in the form of 4n or 4n + 1. I know that when we square any integer greater than 2 the result will be either divisible by four or four divides into the integer and leaves a remainder of one. How would I begin proving this in the most...
  14. C

    What Are the Limit Points of the Set {sin(n): n a Positive Integer}?

    Homework Statement a)Determine at least three limit points for the set {sin(n): n a positive integer} b)How many limit points does the set {sin(n): n a positive integer} have? The Attempt at a Solution For a it seems that it wouldn't have a limit point because sin(n) would not converge to...
  15. L

    Limit of the greatest integer number

    Hi there, It is clear that \lim_{n\to\infty }\frac{1}{n}\left[\frac{n}{3}\right]=\frac{1}{3}. But the problem that I could not get a formal proof! Thank you.
  16. M

    How are error margins determined without using an integer for population?

    My first post on these forums, was referred here by a friend of mine. Thanks in advance! Mind that this question is coming from a BA in psych's worth of understanding: If I understand correctly, estimations of error margins are based on the relationship between a population and a sample of...
  17. D

    Non Integer Exponents for Cartesian Products

    I know the Cartesian product for an algebraic structure: A x B = {(a,b): a ∈ A, b ∈ B} Which naturally gives An = {(a1, a2, ... , an): ai ∈ A ∀ i} Some of the time, at least we can also have a non integer n. For example [A x A x A]2/3 = A x A. Is there any way of continuing the...
  18. J

    Prove each nonzero integer may be uniquely represented

    Homework Statement prove that each nonzero integer may be uniquely represented in the form e0 + e131 + e232 + ... + ek-1ek-1 + ek3k where ek =/= 0 and each ek = -1, 0, or 1. Homework Equations The Attempt at a Solution I feel like this has to do with the basis representation theorem because...
  19. E

    B^2 = a with a is an integer and b rational => b is an integer

    Homework Statement b^2 = a b is a rational number a is an integer prove that b is an integer. This is self assigned, but I think this is the appropriate place to put my question. Homework Equations see above The Attempt at a Solution Is this legitimate...? Since b is a...
  20. Saladsamurai

    C/C++ C++:How to Make sort function work with Double and Integer type

    So I have a simple selection sort function written. It takes an array of type [FONT="Courier New"]double as the array to be sorted. If I declare the array to be of type [FONT="Courier New"]int in my [FONT="Courier New"]main program and then pass it to my sSort function, it gets mad. There must...
  21. S

    When is m33 divisible by 36? (m is an integer).

    Homework Statement Work out the order of the following elements; 33 \in Z_{36}The Attempt at a Solution It's probably really simple. But this only happens when an integer times 33 is divisible by 36. That is; 33n = 36m Which I can re-arrange to find n = 36m/33 Now, I can keep adding...
  22. P

    Proving non-existence of integer solutions by reducing mod p

    Say I have the equation a^2 - 10b^2 = 2. So even though this is an equation in two variables and not one, I can still reduce mod P to a^2 = 2 (mod 5) and use the fact that it has no integer solutions mod 5 to conclude the original equation has no integer solutions, correct? Also does this only...
  23. T

    Floor Function (Greatest Integer Function) Identity

    Homework Statement Prove that, for all x, y \in \mathbb{R}, [2x] + [2y] \geq [x] + [y] + [x + y]. Homework Equations I am using [\cdot] to represent the floor function, and \{\cdot\} to represent the fractional part of a real number (\{x\} = x - [x] for real numbers x). We may...
  24. N

    Number of integer solutions to x^2 + y^2 <= n? [simple proof]

    Homework Statement I am stuck on a step from a simple proof in Gelfand's method of coordinates. Here is a link to the part I am confused on. Pg. 44-45...
  25. R

    C# Converting integer into array of single digits in C#?

    Whats the easiest way to take an integer in C# and convert it into an array of length equal to the number of digits and each element is a digit from the integer? EG. If I had the integer 12345 I want to convert it to an array like so {1, 2, 3, 4, 5} Thanks AL
  26. B

    Weird Integer Progression in Language Whose Name I Failed to Catch

    Right now I'm watching a US Public Broadcasting Corporation television program entitled: "The Linguists", in which a man (I think he was from Africa, but I'm not even certain of that, as I wasn't even listening until the math stuff surfaced), explaiined his integer progression, which was quite...
  27. E

    Inherent negativity of seemingly symmetric finite integer sets

    Hi everyone. My first post on this great forum, keep up all the good ideas. Apologies if this is in the wrong section and for any lack of appropriate jargon in my post. I am not a mathematician. I have a theory / lemma which I would like your feedback on:- Take a finite set S of integers which...
  28. L

    Finding limit- greatest integer function

    Hi, I was studying for my upcoming calculus exam and couldn't be sure if I could solve this question: \stackrel{lim}{x\rightarrow0} x [\frac{1}{x} ] If x approaches 0 from left, then 0< x [\frac{1}{x} ]<1 If x approaches 0 from right, then x [\frac{1}{x} ]>1 since x [\frac{1}{x}...
  29. Z

    C/C++ Converting string to integer using atoi in C++

    Hello, the problem that I was asked to complete was ; Write a program that inputs a string and reverses it. After the string has been reversed you must convert it to an integer and then take the square root of the integer. (using atoi) My code is as follows: int main () { int i=0,L=50...
  30. S

    Discrete Mathematics: Proof problem for even integer

    Homework Statement For every non-negative integer z, z2 - 3z is an even integer. Prove this statement. So far, I have learned about direct proofs and indirect proofs such as contraposition and contradiction. Homework Equations An integer z is odd when there is an integer a so that z = 2a+1...
  31. F

    Are the charges of electrons necessarily integer values?

    It seems as if the charge we have labelled the electron with has simply been inferred by comparing it to the proton, in which case it is pretty much exactly the opposite, so we give the proton and electron charges of +1 and -1 respectively. This is fine, but when we get to the standard model...
  32. E

    Integer values of this expression

    Is there a simple way to find the integer values of f(x)=(a+5x)/(6x+1) with a, x integers.
  33. G

    Proof by contradiction - For any integer n, n^2 - 2 is not divisible by 4.

    Homework Statement Just as the title said, I need to prove: For any integer n, n2 - 2 is not divisible by 4 by the method of proof by contradiction. Homework Equations (Relevant by division into cases) Even numbers = 2k for some integer k Odd numbers = 2m+1 for some integer m...
  34. M

    What is the concept for solving equations with integer parts?

    Homework Statement 2*[x]-3*[3x]+7=0 Homework Equations solve for x when [x] is the integer part of the number. The Attempt at a Solution To solve it i removed the brackets and got x=1 and then i found the integer part of 1 is 1. Is it correct? If not is there a concept to...
  35. V

    Find all integer solutions to

    Find all integer solutions to ... Homework Statement Find all integer solutions to \begin{array}{l} {a^2} = a + b - 2c + 2d + e - 8\\ {b^2} = - a - 2b - c + 2d + 2e - 6\\ {c^2} = 3a + 2b + c + 2d + 2e - 31\\ {d^2} = 2a + b + c + 2d + 2e - 2\\ {e^2} = a + 2b + 3c + 2d + e - 8 \end{array} ...
  36. T

    Half integer orbital momentum, following Griffiths

    Hello everyone, and thanks for reading. I'm having a difficult time understanding something. On yet another attempt to deepen my quantum mechanics understanding I referred to the widely recommended book of Griffiths. I find the book indeed very good and pretty thorough in it's scope. There...
  37. A

    Integer solution to exponential diophantine equation

    Hey everyone! I was recently scribbling on paper, and after a series of ideas, I got stuck with a problem. That is, can I find out if there exists some integers A and B such that C=2^{A}3^{B} For some integer C? For an arbitrary C, how do I know whether some A, B \in \textbf{Z}...
  38. F

    1 equation, 2 unknowns, need integer solution

    Homework Statement I needed to solve this single equation with two unknowns. 199x - 98y = -5 0< x <=99 0< y <=99 I typed the equation into Wolfram Alpha and got an integer solution of: x = 98n + 31 y = 199n +63 when n is an integer Since I know my restriction on x and y I can...
  39. 7

    Can the integer zeros for this diophantine equation be found?

    Hello every one, please help me finding the integer zeros for this equation -15x^3+45x^2y-15xy^2+y^3+90x^2-210xy+40y^2-120x+184y = 0 I know that the solution should used by diophantine equation but i don't know ho to solve it, Please help :(
  40. C

    Integer Length for Intel Core 2 Duo (MAC OSX)

    Hello all, I am trying to determine if my machine is 64 bit or 32 bit, according to this site: http://support.apple.com/kb/ht3696" the Intel Core 2 Duo I am using is 64 bit, but when I run the following code #include <stdio.h> int main(int argc, char **argv) { char c; int...
  41. I

    Solving Hexadecimal Unsigned 8-bit Integer Multiplication

    Homework Statement a) 50 b) 23 Product of the hexadecimal unsigned 8-bit integers Homework Equations Step Action |||||||||| Multiplicand ||||||| Product/Multiplier 0 Initial Vals ||||||||| 101 000 ||||||| 000 000 010 011 The Attempt at a Solution How...
  42. B

    Division of integer square by 4 leaves remainder 0 or 1

    Hi, I am looking for an explanation, if any, on why every integer square leaves remainder 0 or 1 on division by 4. Appreciate your time and help bluemoon2188
  43. D

    Explaining discontinuity in a greatest integer function

    Homework Statement Find the numbers, if any, where the function is discontinuous. f(x) = [[x - 2]] The attempt at a solution function is discontinuous for all integer values of x. I know that this is the obvious answer, however I am required to explain this in clear mathematical...
  44. S

    What is the Integer Program Formulation for Maximizing Scores in a Word Puzzle?

    Homework Statement Consider the following puzzle. You are to choose 4 three-letter "words" from the following list: ECB EFH BEJ GGE HIJ CDE GEG CBJ For each word, you earn a score equal to the position that the word's third letter appears in the alphabet. For example, ECB earns a score...
  45. L

    Integer Spin and Half Spin: What's the Difference? (Bosons vs. Fermions)

    bosons have integer spin, fermions have half spin, what does that mean? why bosons (integer spin) is able to avoid pauli's exclusion principle?
  46. S

    Integer factorization given enough primes

    I realize that this might seems to be a strange question, but after doing some coding i realized the following. to brute force the factorization of all numbers less than one million takes around 665 million tests (i.e. does this number divide the original). to do it "smarter" (least i...
  47. G

    Generating division problems with integer results

    I'm not sure at all how best to approach this problem. Basically, the application is for practicing mental arithmetic. Most of the features are pretty easy, with the exception of division, which is the topic here. I accept a minimum and maximum for the first and last numbers in the division...
  48. O

    Assignment makes pointer from integer without cast

    "assignment makes pointer from integer without cast" elephant* get_elephants() { elephant *current, *first; int response; /* create first node */ first = (elephant*)calloc(1,sizeof(elephant)); /* THIS LINE */ current = first...
  49. F

    Finding the aproximate integer Sqrt of a large prime

    I am trying to understand how I can find the square root of a large prime number in the form of an integer value, the portion after the decimal is irelevant. The numbers I wish to compute range around 188 multiplied by 3 to the power of 6548 plus 1, as an example. so let's say in excess of...
  50. K

    Smallest Positive Integer N for which tow(n)=6 is True

    Find the form of all n in N satifying tow(n)=6. (sorry don't know how to write this Tex). What is the smallest positive integer n for which this is true? tow(n)=6 so 6=(1+a1)(1+a2)----(1+ak) where n=p1^a1p2^a2---pk^ak
Back
Top