How could I mathematically prove these statements?
1. The sum of the first n positive odd numbers is square.
2. Two positive numbers have the same set of common divisors as
do the smallest of them and their absolute difference.
3. For every prime p > 3, 12|(p 2 − 1).
prove that for x is an odd, positive integer, 3x ≡−1 (mod 4).
I'm not sure how to approach the problem. I thought to assume that
x=2a+1 and then show that 3^x +1 is divisible by 4 and thus
congruent to 3x=-1(mod4) but I'm stuck.
Let us divide the odd positive integers into two arithmetic
progressions; the red numbers are 1, 5, 9, 13, 17, 21, ... The blue
numbers are 3, 7, 11, 15, 19, 23,....
(a) Prove that the product of two red numbers is red, and that
the product of two blue numbers is red.
(b) Prove that every blue number has a blue prime factor.
(c) Prove that there are infinitely many blue prime numbers.
Hint: Follow Euclid’s proof, but multiply...
By constructing a suitable bijection, show that the number of
subsets of an n-set of odd size is equal to the number of subsets
of an n-set of even size.
Please prove
1. Every positive integer is a product of prime numbers.
2. If a and b are relatively prime, and a|bc, then a|c.
3. The division algorithm for F[x]. Just the existence part
only, not the uniqueness part
Prove the following statements by using the definition of
convergence for sequences of
real numbers.
a) If {cn} is a sequence of real numbers and {cn} converges to 1
then {1/(cn+1)} converges to 1/2
b) If {an} and {bn} are sequences of real numbers and {an}
converges A and {bn} converges to B and B is not equal to 0 then
{an/bn} converges to A/B