Answer:
[tex]"i"[/tex]
Step-by-step explanation:
[tex]i =\sqrt{-1} \\i^{2}= -1\\\\i^{3}= -i\\\\i^{4}= 1\\\\i^{5}= i\\[/tex]
the cycle repeats every 4
19/4 = 4.75
16 is divisible by 4 plus three more
thus [tex]i^{19} = -i[/tex] but you problem has a minus in front so "i"
