Answer only one of the following two alternatives. EITHER State the fifth roots of unity in the form cos θ + i sin θ, where –π < θ ≤ π. Simplify (x − [cos(π/5) + i sin(π/5)]) (x − [cos(π/5) − i sin(π/5)]). Hence find the real factors of x⁵ - 1. Express the six roots of the equation x⁶ - x³ + 1 = 0 as three conjugate pairs, in the form cos θ ± i sin θ. Hence find the real factors of x⁶ - x³ + 1.
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