For centuries, mathematicians worked only with real numbers, which could be plotted on a number line. However, in the 16th century, while solving equations like $x^2 + 1 = 0$they realized that, in order to solve such an equation, they had to introduce square roots of negative numbers. Today the number $ i = \sqrt{-1}$ is known as imaginary unit. When combined with real numbers, the imaginary unit can be used to represent any *complex number* $z$ of the form $z = a + b\cdot i.$ Today, complex numbers play a crucial role in engineering, physics, and computer science. They provide a way to analyze [[Wave|wave]] behavior, [[Electronic Circuit|electronic circuits]], and even [[Quantum Mechanics|quantum mechanics]]. >[!read]- Further Reading >[!ref]- References