What is a complex number?

A complex number is one that is made up of a complex and real part, they can all be written as:

a+bi, where a and b are real numbers.

The thing that makes the number "complex" is "i", the imaginary number. "i" is the square root of -1, so if you had "square root of -4" your answer would be "root 4 times by i" or "2i".

It has many applications, particularly in Pure Mathematics.

James B. A Level Maths tutor, GCSE Maths tutor

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