Cevap:
# J = 8 #
Açıklama:
#costheta = ((a + jb).c) / (abs (a + jb) abs (c)) #
Ancak, # Teta = 90 #, yani # Cos90 = 0 #
# (A + jb).c = 0 #
# A + jb = ((2), (2), (2)) + j ((- 1), (2), (1)) = ((2j), (2 + 2j), (2 + j)) #
#c = ((3), (1), (0)) #
# (A + jb).c = 3 (2j) + 2 + 2j = 6-3j + 2 + 2j = 8-f = 0 #
# J = 8 #