i (Unit Imaginary Number) | more ... |
 The square root of minus 1. The symbol is "i" When you square any Real Number you always get a positive, or zero, result. For example 2×2=4, and (-2)×(-2)=4 as well. So how can we square a number and get a negative result? Just "imagine" that we can, and it turns out that such a number, which may seem impossible, is actually useful and can solve real problems. See: Real Number | |