Negative exponent
A negative exponent describes a fraction
Example 0
In school you learned
You must know then already that 20 = 1 and 21 = 2.
Example 1
A negative exponent may be a rational number
Example 2
A division by zero is not defined, so
Example 3
You can calculate the reciprocal of the imaginary unit as
because the imaginary unit has no real value.