What are complex numbers? I mean what is their significance?

Imaginary/complex numbers are multiples of i. Like 2i, 4i, 2.881i etc... They arise because not all equations can be solved by using only real numbers. Real numbers are all numbers ranging from - infinity to + infinity.

For example, we cannot solve x^2 + 1 = 0 using real numbers. This is where imaginary numbers step in. If we "define" the square root of -1 to be i, then we can solve the above equation by saying x = i.

Imaginary/complex numbers are multiples of i. Like 2i, 4i, 2.881i etc... They arise because not all equations can be solved by using only real numbers. Real numbers are all numbers ranging from - infinity to + infinity.

For example, we cannot solve x^2 + 1 = 0 using real numbers.This is where imaginary numbers step in. If we "define" the square root of -1 to be i, then we can solve the above equation by saying x = i.