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# What are imaginary numbers in maths?

My boyfriend claims that there is such a thing as imaginary numbers in maths, I think he is making it up... Ever heard of that?

### 13 Answers

- Anonymous1 decade agoFavorite Answer
An imaginary number is a root of a negative number. ( i = the square root of negative one, and 2i is the square root of negative four, etc...)

"Imaginary" numbers have gotten themselves quite a negative reputation, but the truth is they are no more real or imaginary than other numbers. (When was the last time you got into an argument with a million?) Numbers are just the way we represent qualitative features of our universe. For example, when society progressed to the point where we needed to evaluate one person's debt to another, negative numbers were developed. People were baffled by the concept, but they did what they were supposed to do, and now they are accepted as fact. Imaginary numbers are the same, though their applications are more vague, like the motion of electricity in a circuit, or in the phases of quantum particles.

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- Anonymous4 years ago
'x' is a variable, an unknown. An imaginary number is i, the square root of -1. Unless x = i, they are not the same. The unknown is simply what you are trying to find; an imaginary number has a known value.

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- Anonymous1 decade ago
No, he is not making them up.

The number -1 has no real square root, because any real number times itself is nonnegative (and therefore not -1).

However, if we introduce a new number "i" and say that "i" equals the square root of -1, then a lot of the properties of the real numbers extend very nicely to work with "i". "Imaginary numbers" are numbers which are multiples of "i."

The set of all numbers of the form "a + b * i", where a and b are real numbers, are called the "complex numbers." The complex numbers (in many ways) work even more nicely than the real numbers, and are used extensively in advanced mathematics.

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- Mad ProfessorLv 41 decade ago
Imaginary numbers are the square roots of minus numbers. Usually represented as multiples of i (the square root of minus one). Eg sqrt(-4) = 2i.

Complex number are ones that have both real and imaginary parts.

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- 1 decade ago
Imaginary numbers are the square roots of negative numbers. They are denoted by the letter 'i'. For example, sqrt(-1) = i and the sqrt(-4) = sqrt(-1) x sqrt(4) = 2i.

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- 1 decade ago
It's something that can't exist in real life: SQRT of a negative number. (any number squared is positive). So why worry about it? Sometimes it's easier to convert to imaginary numbers, do the calculation and then convert back to real numbers. This technique is used a lot by electrical engineers to figure electrical power equations. sqrt(-1) = i

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- SheenLv 41 decade ago
Yes, imaginary numbers are very good mathematical tools existing.

Denoted by i = sqrt(-1)

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- Jerry PLv 61 decade ago
sqrt(-1) = i

i is the basis for the pure imaginary numbers.

Imaginary and real numbers can be combined to form *complex* numbers: 3 + 2i is a complex number.

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- 1 decade ago
Yes I think there are imaginary nos but might be called something else. It is when performing a mathematical problem it cannot be solved. Therefore you have to add a nos (imaginary) for it to work.

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- efes_hazeLv 51 decade ago
For some reason in electrical engineering, the square root of -1 is known as j and not i.

Used a heck of a lot.

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