Find the value of following expression:

i + i2 + i3 + i4

i + i2 + i3 + i4 = i + i2 + i2×i + i4


= i – 1 + (– 1)×i + 1


since i4 = 1, i2 = – 1


= i – 1 – i + 1 = 0


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