2007-12-29 02:15:31 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Yes.
It's certainly not composite.
By convention, the primes start with two.
2007-12-29 02:19:11 · answer #1 · answered by Anonymous · 3⤊ 0⤋
That's true. By definition a prime number must be
greater than 1.
You may ask: Why isn't 1 a prime?
The answer is: If 1 were prime the law of unique
factorisation would no longer hold.
Recall that the law of unique factorisation says that
every positive integer can be written as a product of primes
and that this product is unique except for the order of the
factors.
If 1 were prime we could tack as many 1s as we
want to the end of this product and it would no
longer be unique.
Example: 12 = 2²*3.
If 1 were prime, we could write 12 = 2² * 3 = 2²*3*1 = 2²*3*1*1, etc.
2007-12-29 10:43:53 · answer #2 · answered by steiner1745 7 · 3⤊ 0⤋
It is neither prime nor composite. It is what is called a unit - a number which is a factor of every other number.
1 and -1 are the only units.
2007-12-29 10:28:50 · answer #3 · answered by jim n 4 · 2⤊ 0⤋
Yes, you are right.
1 is not a prime number because:
a prime number has TWO factors but 1 just has only ONE factor.
1 is not a composite number because:
a composite number has more than TWO factors but 1 just has ONE factor.
That's why 1 is neither a prime number nor a composite number.
2007-12-29 12:07:16 · answer #4 · answered by An ESL Learner 7 · 0⤊ 1⤋
A composite number is by definition a number that is greater than 1 that is not a prime - so 1 can't be composite.
For a time it was held by some that 1 was a prime number, but then when the Fundamental Theorem of Arithmetic came along, it was realised that for that to work, 1 couldn't be prime. In order to save themselves a lot of work changing proofs and work that depended on the Fundamental Theorem of Arithmetic, it was just easier to say 1 wasn't prime.
2007-12-29 10:29:50 · answer #5 · answered by Richard Hammings 1 · 2⤊ 1⤋
1 Is not Prime or Composite. We JUST learned about that in school.
2007-12-29 10:23:53 · answer #6 · answered by mrs_joe_jonas_45 2 · 3⤊ 0⤋
Yes, for a (natural) number to be prime or composite is necesary that such number must be greater than 1. Is not by convention, is by definition.
2007-12-29 10:20:08 · answer #7 · answered by obueno 2 · 2⤊ 0⤋
1 is not prime because every prime number has exactly two whole number factors. 1 has only one whole number factor, 1.
1 is not composite because it has no prime factors.
2007-12-29 10:50:49 · answer #8 · answered by Arnold K 2 · 1⤊ 1⤋
1 is prime
2007-12-29 10:19:29 · answer #9 · answered by Wolfe 3 · 0⤊ 5⤋