Number of integral values of n for which the quantity (n+i)4 where i2=−1 , is an integer is

(n+i)4=n4+4n3i+6n2i2+4ni3+i4             =n4−6n2+1+i(4n3−4n)  For this to be integer,4n3−4n=4n(n2−1) must be zero⇒  n=0   or  n=±1   ⇒ 3 values