<span>i^1=i</span><span>i^2=-1</span><span>i^3=i^2*i=-i</span><span>i^10=-1</span><span>i^11=-i</span><span>i^12=1</span><span>i^13=i</span><span>Вообще, можно доказать, что:</span><span>i^4n=1</span><span>i^(4n+1)=i</span><span>i^(4n+2)=-1</span><span>i^(4n+3)=-i</span><span>n=0,1,2,3,...</span>
у=2*(-2)+1=3
вроде так