SOLUTION: How do I prove that a prime number cannot be a sum of two or more consecutive positive odd integers? This is my 7th grade extra credit. I wrote a list of primes. I have added

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: How do I prove that a prime number cannot be a sum of two or more consecutive positive odd integers? This is my 7th grade extra credit. I wrote a list of primes. I have added       Log On


   



Question 682679: How do I prove that a prime number cannot be a sum of two or more consecutive positive odd integers?
This is my 7th grade extra credit. I wrote a list of primes. I have added consecutive odd integers randomly. I know a prime cannot be the sum. I think there is a formula. x+[x+2]?? something with the powers of 2?
Please help
Ty

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Let represent any positive odd integer. Then is the next consecutive positive odd integer.

The sum of these two positive odd integers is

Assume that is prime. But is divisible by 2 and therefore even. The only even prime number is 2, hence:



Which means that . But is neither positive nor odd, contradicting the original assumption about the nature of . Therefore, reductio ad absurdum, cannot be prime for any positive odd value of . Q.E.D.

John

Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
The Out Campaign: Scarlet Letter of Atheism