Closed

 This is too cute: showing what a 1 radian angle expresses on the Unit Circle.

Radians (mathsisfun.com)

That circle was - avant l'heure - a calculation machine. Everything is expressed

in terms of everything else. And there is a variant with values of i on the y-axis.

Mathematically, it is closed. 

It should not be surprising that  complex exponents are calculated with the help

of trigonometric functions...

                                                           *     *     *

Found this lovely cubic equation on the Russian language Wikipedia.

Oops! not all roots are real...

Below, one where they are:

                                                                     

Would like to clarify all this, for today's task!