Imaginary unit
The imaginary unit i is formally defined as the square root of –1, so
whatever that may be.
Explanation
This definition is clearly out of date, but is unfortunately still often used in school books. The current definition of the imaginary unit is
Example 1
The ascending powers of i give
Because i4 = 1 this continues with
and these values repeat themselves again and again.
HistoryThe Italian mathematician Rafael Bombelli published the book L'ALgebra in 1572 where arithmetic with complex numbers was clearly explained. |