mod

  1. A

    Show that x^2 is congruent to 1 (mod 24) given x congruent to 5 (mod 6)

    Hi all, I will write out the word congruent instead of the symbol, as we use three lines over one another and I could not find a way to write it out. The question: "Let x be congruent to 5 (mod 6). Show that x^2 is congruent to 1 (mod 24)." I believe I need to set up one equation as indices...
  2. C

    how to prove multiplicative integers (mod p) has at least one generator?

    How do you prove the multiplicative integers (mod p) has at least one generator? I know how to show a^(p-1) is congruent to 1 using Fermat's Little Theorem but how do you show p-1 is the smallest such integer? Thanks!
  3. D

    Proof: If q is a prime divisor of 2^p -1, then q ≡ 1 (mod p)

    Let p be a prime number and M = 2^p − 1. Let q be a prime divisor of M. Prove that q ≡ 1 (mod p). I'm completely stuck. Help please?
  4. alexmahone

    Show that n=1 (mod 9)

    Show that $n\equiv 1 \pmod 9$ for all even perfect numbers $n>6$.
  5. P

    mod and div questions

    Hi , Sorry for posting simple questions but I don't know how to solve these questions : Q1 : The smallest positive integer a such that a + 1 ≡ 2a (mod 11) is ...ANSWER IS 12 Q2 : Find –151 div 20 ANSWER IS -8 Q3 : Find –151 mod 20 ANSWER IS 9 thanks a lot.
  6. B

    Find an inverse for (x^2+2x+1) (mod x^3 +x^2+1) in Z_3

    So I have (x^2+2x+1)q(x) \equiv 1 \mod{x^3 +x^2+1} over \mathbb{Z}_3 And the goal is to find $q(x)$ I'm working off a partial solution and I'm trying to fill in the holes at the moment. So firstly we check if the modulus is reducible/factorable, since it has a root $(f(x)=1+1+1=3=0)$ it is...
  7. B

    Find a multiplicative inverse of a polynomial mod (x^2-2)

    (a+bx)q(x) \equiv 1 \mod {x^2-2} Since we're concerned only with remainders and the modulus is second order, $q(x)$ must be linear. So we set $q(x)=(c+dx)$ (a+bx)(c+dx) \equiv 1 \mod {x^2-2} ac+adx+bxc+bdx^2 \equiv 1 \mod {x^2-2} Substituting $x^2=2$ and rewriting gives, (ac+2bd)+(ad+bc)x...
  8. I

    Find the least residue of the multiplicative inverse of a mod m

    A) a=7, m=11 B)a=7, m= 23 C)a=5, m=31 D)a=117, m=24
  9. A

    integration of mod x - regarding

    kindly help me how to integrate mod x ? there is no limits for the integration; indefinite integral. with warm regards, ARANGA
  10. T

    Prove that if m, d, and k are integers and d > 0, then (m + dk) mod d = m mod d.

    Im having trouble with this proof. Could someone help me? Prove that if m, d, and k are integers and d > 0, then (m + dk) mod d = m mod d.
  11. J

    show (m + dk) mod d = m mod d

    I just learned about mod, I know that for example 10 mod 3 = 1, 1 being the remainder of 10 divided by 3 we just covered induction but I don't feel this is a problem that can be solved by induction, or not in what I have learnt thus far question is: If m, d, k \mathhbb{Z} and d>0 then prove...
  12. M

    mod 7

    find the smallest positive integer b which satisfies 3^56=b(mod7) I am very new to modular arithmetic and I stubbled upon this question. Wouldn't 'b' have a specific solution. Asking for the smallest positive integer b confuses me. 3^{56} - b = 7k \;\;\text{ Where k is an integer} when...
  13. H

    Calculation in Rijndael field GF(2^8) and (mod x^4+1)?

    I have a 6th degree polynomial with unknown coefficients, but I need to take it (mod x^4+1) to find some 3rd degree polynomial. Using wolfram alpha and mathematica 9.0, I could only reduce the polynomial to a different 6th degree polynomial that was shorter. e.g. a_1x^6 + a_2x^5 + ... a_6x...
  14. V

    Prove that σ(n)≡d(m) (mod 2) where m is the largest odd factor of n.

    Prove that σ(n)≡d(m) (mod 2) where m is the largest odd factor of n. need elaborate and quick reply please.
  15. X

    For which n is 1^2 + 2^2 + ... + (n-1)^2 ≡ 0 mod n true?

    For which n ≥ 2 is the following true; 1^2 + 2^2 + ... + (n-1)^2 ≡ 0 mod n I've tried some numbers and found that it works for 5 but I'm not exactly sure why that is. I'm aware of that 1^2 + 2^2 + ... + (n-1)^2 is the sum of every element in complete residue system for n multiplicative by...
  16. U

    prove there is no primitive root mod 3p

    when p odd , p>3. --------- I don't know how to cintinue: a^(p-1)=1(modp) a^2=1(mod3) ....
  17. S

    solving for x in 78^x =x (mod 10^12)

    Hi Guys, Any idea how to solve the equation 78^x = x (mod 10^12) ? Assume that x is a 12 digits number I've looked over every congruence and can't seem to find anything useful.
  18. M

    Show a^n = 1 (mod 2^n+2) if a odd.

    I know I have to use induction. The n=1 is simple: a^2 = (2j+1)^2 = 4j^2 + 4j + 1 = 1 mod 8 = 1 mod 2^3 Then we assume for a^n that the claim is true. However I'm not sure on the inductive step. This is a HW assignment and help would be much appreciated. Thanks!
  19. J

    Find (10^5)^101 (mod 21)

    .