What is Integer: Definition and 620 Discussions

An integer (from the Latin integer meaning "whole") is colloquially defined as a number that can be written without a fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, 5+1/2, and √2 are not.
The set of integers consists of zero (0), the positive natural numbers (1, 2, 3, ...), also called whole numbers or counting numbers, and their additive inverses (the negative integers, i.e., −1, −2, −3, ...). The set of integers is often denoted by the boldface (Z) or blackboard bold



(

Z

)


{\displaystyle (\mathbb {Z} )}
letter "Z"—standing originally for the German word Zahlen ("numbers").ℤ is a subset of the set of all rational numbers ℚ, which in turn is a subset of the real numbers ℝ. Like the natural numbers, ℤ is countably infinite.
The integers form the smallest group and the smallest ring containing the natural numbers. In algebraic number theory, the integers are sometimes qualified as rational integers to distinguish them from the more general algebraic integers. In fact, (rational) integers are algebraic integers that are also rational numbers.

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  1. C

    Questions on Remainder & Integer Divisibility

    I have 2 questions. 1)what is the remainder with 100! is divided by 103? explain your answer 2)a = 238000 = 2^4 x 5^3 x 7 x 17 and b=299880 = 2^3 x 3^2 x 5 7^2 17. Is there an integer so that a divides b^n? if so what is the smallest possibility for n? the first one i have no...
  2. S

    Proof by induction: nCr always an integer

    Hello all, I've been asked for a graduate level course to do a proof using induction that shows that nCr always turns out to be an integer. I thought that I might use Pascal's triangle somehow and the fact that nCr is equal to n! / r!(n-r)! (I saw a brief explanation of this while doing a web...
  3. S

    Question about sum of integer involving factorial notation

    I have my question and my problem in the attachment that followed.
  4. A

    Integer value of the longest possible side of a triangle

    Hai COuld you please help the formula as I am not able to identify the question below: Question: For a Traingle with a perimeter of 30cm, what is the integer value of the longest possible side ? REgards aprao
  5. G

    Why Does Integer Arithmetic in Haskell Seem Inconsistent?

    Can anybody explain what appear to be discrepancies in the way the following expressions are interpreted by Hugs (Haskell98 mode) ? Main> div -6 4 ERROR - Cannot infer instance *** Instance : Num (b -> a -> a -> a) *** Expression : div - fromInt 6 4 Main> div (-6) 4 -2 Main> -6...
  6. G

    What is the Cost Function for a Long Distance Call?

    I just completed Trigonometry and College Algebra, and I'm heading into Calculus, so i thought i would get a head start on the material. So right now I'm working out of an old calculus book i got at the library. Then i came across this problem: A dial-direct long distance call between two...
  7. B

    Proving Finite Solutions of phi(x)=n for Fixed Integer n

    for n- fixed integer prove that phi(x)=n has a finite number of solutions I looked at 2 cases when x is even and when x is odd 1) if x is even then phi(2x)>phi(x) and I showed why it has a finite number of solutions 2) I'm not sure how to show for the case when x is odd.. any ideas? thanks :)
  8. K

    Reciprocal Series of Positive Integer Factors: Convergence & Sum

    The terms of this series are reciprocals of positive integers whose only prime factors are 2s and 3s: 1+1/2+1/3+1/4+1/6+1/8+1/9+1/12+... Show that this series converges and find its sum. this is my first time writing here. i hope someone can help me with this question.
  9. O

    How many pairs of positive integer a, b

    How many pairs of positive integer a, b are such that a^2 + b^2 = 121?
  10. Y

    Prove that the square of an odd integer

    I'm not a very logical person, and I would hardly consider math a strength so, I'm stuck with these proofs: 1. Prove that every positive integer, ending in 5 creates a number that when squared, ends in 25 2. Prove that if n is an even positive integer, then n^3 - 4n is always divisible by...
  11. F

    Prove that an integer with digits '1' is not a perfect square.

    I am having trouble with this one... Prove that any positive integer whose ALL digits are 1s (except 1) is not a perfect square.
  12. N

    Searching for a non-negative integer

    I have an integer A and a possitive odd integer B, can you tell me how to find a nonnegative integer C such that C<2^A and 1+BC=0(mod 2^A) ? ?
  13. I

    Understanding the Integer 'x'".

    "x is an integer" "x is an integer" is a sentential function, right?
  14. P

    Partition of Integer need advice

    The Q is: show that the number of partitions of n within Z+ where no summand is divisible by 4 equals the number of partitions of n where no even summand is repeated Here is what I got so far Let the partition where no summand is divisible by 4 be P1(x) Let the partition where no even...
  15. I

    Solve a radical equation where the root is a negative integer?

    Is it possible to solve a radical equation where the root is a negative integer?
  16. E

    Understanding x=pmodn: An Integer Modular Arithmetic Primer

    What does x=pmodn mean where x,p,are integers and n is a natural number?
  17. M

    What is Non-Integer Calculus and How Does it Work?

    Seem to remember reading about RF experimenting with non-integer differentiation. I found it quite interesting to play with. I started with 'half' differentiation. e.g. f(x) = x^2 , D[1]f = 2x , D[2]f = 2 but what about non-integer diff? e.g. D[0.5]f = px^1.5 what is p? Clearly...
  18. Y

    Greatest integer divides p^4 -1

    What is the greatest integer divides p^4 -1 for every prime number p greater than 5? It is 240. Why? Thanks!
  19. M

    Derive the following, for any integer k

    I really need someone to answer this by tomorrow 12/01 10:50 am pacific time... 1) Derive the following, for any integer k. infinity SUM OF: 1/(n^(2k)) = ((2(pi))^(2k)(-1)^(k+1)B2k ) /(2(2k)!) n=1 where Bn is defined by the following, for |x| < 2(pi). ````````````infinity (x)/(e^(x)-1)...
  20. J

    Does |A| = k When a is a Complex Number and k is a Positive Integer?

    if a^k =1 and a \in \mathbb{C} k \in Z^+ and for some k A = \{a|a^k = 1\} does |A| = k ? edited: becasue the real numbers are a subset of the complex numbers
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