Me? =- 1。 (where I is called imaginary unit)

The legal provisions are as follows:

I to the power of 0 =1;

The first power of I = I；;

I = I× I =- 1 square;

The third power of I =-1× I =-I;

I =-I× I =-(- 1) = 1 to the fourth power;

..... and so on,

The 4n power of I =1;

(4n+1) the power of I = the first power of I =i;

(4n+2) power of I = quadratic power of I =-1;

The (4n+3) power of I = the third power of I =-I.