which are 'prime number' & 'complex number' ?

Question

1 to 20

Answer 1

2,3,5,7,11,13,17,19 are prime numbers

complex numbers:
z=a+bi
example
z=5+14i

Answer 2

Any number that can only be divided evenly by itself and 1 is considered a prime. There is some debate as to whether 1 is a prime. Though it does fit that criteria, it is not considered (by most) to be "prime."

1
2
3
4 = 2 x 2
5
6 = 2 x 3
7
8 = 2 x 4
9 = 3 x 3
10 = 2 x 5
11
12 = 2 x 6 = 3 x 4
13
14 = 2 x 7
15 = 3 x 5
16 = 2 x 8 = 4 x 4
17
18 = 2 x 9 = 3 x 6
19
20 = 2 x 10 = 4 x 5

So, 2,3,5,7,11,13,17 and 19 are prime --remember 1 isn't considered a prime.

Complex numbers are of the form a + bi (where i = √(-1) -- you may have been told there is no such thing... just like a lot of things in math, "you can't do it" often means, "You'll get to it later."
As a matter of fact the Real numbers are a subset of the Complex numbers, including only those complex numbers where b = 0. So all the numbers between 1 and 20 inclusive are complex numbers.

But if you mean "composite numbers," i.e., those numbers that can be expressed as the product of two numbers other than 1 and themselves, then those would be the numbers between 1 and 20 inclusive that are not prime, to wit...
4,6,8,9,10,12,14,15,16,18, and 20

Answer 3

All prime numbers having 2 digits and above have end digits either 1, or 3, or 7 or 9 (in units-position)!

'Less than 10' prime numbers are 2, 3, 5 and 7

A prime number is a positive (whole) number, (which has 'no other whole number factor' in between 1 and 'said prime number itself').

Any "step of '6' number (+/-) 1" is either a prime number or a number having only 'prime number factors'.

Example 6*7=42 and (42+1) or (42-1) are prime numbers!
Example 6*8=48 and (48+1) is 49=(7*7) and both factors are prime numbers! 48-1=47 is yet another prime number!

Complex number is a combination of 'a real number' and a not-real number ! Example is {a+ b*(-1)}... -1 = i^2

In some engineering applications (-1) is regarded as 'j' and related formulae will appear to be fully positive values!

You may work out values in range 1...20 or any higher range!

Answer 4

Come on, you can find the prime numbers between 1 and 20. The first few are 2, 3, and 5 (1 is NOT a prime number). Just find out which ones only have factors of 1 and itself.

The integers 1 through 20 are also all complex numbers, because they can be written in the form of a + bi, though in this case b=0. The set of all real numbers is a subset of the complex numbers.

Of course, whether they're COMPOSITE numbers is another story!

People can give as many thumbs-down on this post as they like, but that doesn't change the fact that 1 is NOT a prime number, and that all real numbers are also complex numbers.

Answer 5

There are no complex numbers between 1 and 20.

The prime numbers are:
2, 3, 5, 7, 11, 13, 17, 19

Answer 6

Ans
Prime Numbers:
Numbers having factors as 1 and the number itself is called a Prime number.
The prime numbers b/w 1 and 20 are 2 ,3,5,7,11,13,17,19
Here 2 is the only no.that is both even and prime.

Complex numers:
Any numbers that can be writen in the form a+ib where a and b are reals and i=root(-1) is called a complex number.
Note:Complex number set is the super number of all numbers.
Note:
I think your question is abt Prime numbers and Composite numbers.If so, composite numbers are those numbers that can be factored or that can be expressed as a product of different factors in different ways
Ex:
24=12x2
=6x2x2
=3x2x2x2
=3x8
=6x4
=24x1
That is numbers that can be expressed as the product of two numbers other than unity(1) and themselves are called Composite Numbers. The composite numbers from 1 to 20 are
4,6,8,9,10,12,14,15,16,18, and 20

Answer 7

the prime numbers are numbers that can only be divided by 1 or themselves

1, 2, 3, 5, 7, 11, 13, 17, 19

In mathematics, a complex number is a number of the form
a + ib
where a and b are real numbers, and i is the imaginary unit, with the property i^2 = −1. The real number a is called the real part of the complex number, and the real number b is the imaginary part. Real numbers may be considered to be complex numbers with an imaginary part of zero; that is, the real number a is equivalent to the complex number a+0i.

Answer 8

To be prime is a characteristic of the positive integers.

The set of real numbers is a subset of the set of complex numbers where the imaginary part is zero. Thus all real numbers are complex but not the converse.

+ add
I think that Geezah is onto something. You probably meant 'composite' not complex. An integer is either prime or composite.

Answer 9

A prime number is a number which is only evenly divisible by 1 and itself. A complex number is list X + Yi . X is a 'real' number and Yi is an imaginary number. The whole thing is a complex number.

Answer 10

Prime numbers are the numbers which have exactly one factor.Neither more than one nor less than 1. From 1-20, the list of prime numbers is as follows:
2;
3;
5;
7;
11;
13;
17;
19.

In mathematics, a complex number is a number of the form

a+bi (i refers to iota)
where a and b are real numbers, and i is the imaginary unit, with the property i^ 2 = −1. The real number a is called the real part of the complex number, and the real number b is the imaginary part. Real numbers may be considered to be complex numbers with an imaginary part of zero; that is, the real number a is equivalent to the complex number a+0i.

Thus from 1-20, all of the numbers are complex numbers having their imaginary part zero.Like:

01+0i;
02+0i;
03+0i;
04+0i;
05+0i;
06+0;
07+0i;
08+0i;
09+0i;
10+0i;
11+0i;
12+0i;
13+0i;
14+0i;
15+0i;
16+0i;
17+0i;
18+0i
19+0i;
20+0i.

Answer 11

prime numbers are thosewhich are divisible by one and itself and no other:2,3,5,7,11,13,
complex number is a number which is of the form:z=x+iy, where x &y are real &i=sqrt(-1): (-3), 2+3sqrt(-5).