Let (dkdk−1⋯d0)3 be the base 3 representation of integer n ≥ 0. Prove that n is odd if and only if an odd number of the base 3 digits dk, dk−1, . . . , d0 are odd.



Let (dkdk−1⋯d0)3 be the base 3 representation of integer n ≥ 0. Prove that n is...
Q4
Let z = dkdk-1 d2dı be the base 10 representation of an integer x where di,..., dk are digits drawn from 0,...,9. Explain why x d1 + d2 + . . . + dk (mod 9) = so, also, z di + d2 + . . . + dk (mod 3) = and Thus for example to check whether 57,711 is divisible by 9 or 3 we just add up the digits 5 + 7+7+ 1 + 1 =...
1. Let n be a positive integer with n > 1000. Prove that n is divisible by 8 if and only if the integer formed by the last three digits of n is divisible by 8.
Let (di, d2,... .dk) (w1, w2,..., wx)-0 (mod n) be an error detection scheme for the k-digit identification number did2 . . .dk, where 0 〈 di 〈 n. Prove that all transposition errors of two digits di and dj are detected if and only if gcd(ui-y,n) = 1 for i and j between 1 and k
Let n be a nonnegative integer and let F 22 + 1 be a Fermat number. Prove that if is a prime number, then either n=0 or 3--1mod F. [Hint: If n 2 1, use the law of quadratic reciprocity to evaluate the Legendre symbol (3/F). Now use Euler's Criterion (Theorem 4.4).]
Let n be a nonnegative integer and let F 22 + 1 be a Fermat number.
Prove that if is a prime number, then either n=0 or 3--1mod...
Let n be a nonnegative integer and let F 22 + 1 be a Fermat number. Prove that if 3 od F., then F, is a prime number. (Note: This yields a primality test known as Pepin's Test.)
Let n be a nonnegative integer and let F 22 + 1 be a Fermat number.
Prove that if 3 od F., then F, is a prime number. (Note: This yields a primality test known as Pepin's Test.)
3. Let n be an integer. Prove that 2 (n4 – 3) if and only if 4| (n2+3).
1. (Integers: primes, divisibility, parity.) (a) Let n be a positive integer. Prove that two numbers na +3n+6 and n2 + 2n +7 cannot be prime at the same time. (b) Find 15261527863698656776712345678%5 without using a calculator. (c) Let a be an integer number. Suppose a%2 = 1. Find all possible values of (4a +1)%6. 2. (Integers: %, =) (a) Suppose a, b, n are integer numbers and n > 0. Prove that (a+b)%n = (a%n +B%n)%n. (b) Let a,...
Exercise 7 (2 points) Recall the binomial coefficient for integer parameters 0 Sk< n. Prove that Exercise 8 (2 points) Prove the following: if z is an integer with at most three decimal digits aia2a3, then x is divisible by 3 if and only if aut a2 +a3 is divisible by 3. Exercise 9 (3 points) A square number is an integer that is the square of another integer. Let x and y be two integers, each of which can...
Definition of Even: An integer n ∈ Z is even if there exists an integer q ∈ Z such that n = 2q. Definition of Odd: An integer n ∈ Z is odd if there exists an integer q ∈ Z such that n = 2q + 1. Use these definitions to prove only #5: 2. Prove that zero is even. 3. Prove that for every natural number n ∈ N, either n is even or n is odd. 4....
Prove that if m is an odd integer then there is an integer n such that n= 4m+ 1 or n= 4m+ 3. Use a proof by cases.