what is the name of the man who 1st defined primes in 300 Bc?

Question

need help

Answer 1

Euclid! The father of Euclidean geometry as well.

Answer 2

I think you are probably thinking of Euclid.

However shortly thereafter Eratosthanes did some work with primes that to me at least is more interesting.

He developed the Sieve of Eratosthanes that is a methodical way to find prime numbers.

For example to find the prime numbers from 1 to 100 do the following:

Make a table or spreadsheet each cell containing one of the numbers from 1 to 50 (remember, you can't have a prime that is greater than one half of the largest number.

In cells 1 2 and 3, do nothing as these are primes.

you start with the number two and exclude as non-prime the numbers that are multiples of two, 4, 6, 8 . . . 50 since these are the even numbers so they can't be prime.

then move to the next number 3, leave it alone because it's prime but then exclude all the numbers that are multiples of 3: 6, 9, 12, . . . 48.

then go to the next number that hasn't been eliminated: 5. Do nothing with it because it is prime, then eliminate its multiples as prime 10 , 15 , , , 50.

Then go to the next non-excluded number: 7 which is prime and exclude its multiples.

Then the next and so on. As you go through the procedure you'll notice that you are eliminating fewer each time.

When you've done the process until everything is marked either excluded or prime, you should have the following prime numbers,
1 3 5 7 11 13 17 19 23 29 31 37 41 47

You can do this for any number.

Good luck.

tfedge

Answer 3

The Greeks knew about prime numbers prior to 300 B.C. However, Euclid was the first to offer a proof that there are infinitely many prime numbers.
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Prime_numbers.html