Questions
Question 1
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What is always one solution of \(z^n=1\) for positive integer \(n\)?
Question 2
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How many distinct complex roots does \(z^7=1\) have?
Question 3
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List the square roots of unity.
Question 4
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Write the fourth roots of unity in rectangular form.
Question 5
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Write the cube roots of unity in exponential form.
Question 6
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Find the argument spacing between adjacent sixth roots of unity.
Question 7
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List the sixth roots of unity in exponential form.
Question 8
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Show that \(e^{4\pi i/5}\) is a fifth root of unity.
Question 9
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Write the fifth roots of unity using \(k=0,1,2,3,4\).
Question 10
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Convert the primitive cube roots of unity to rectangular form.
Question 11
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Verify that the four fourth roots of unity all have modulus \(1\).
Question 12
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Explain why using \(k=0,1,\ldots,n-1\) gives all independent roots of \(z^n=1\).
Question 13
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Find the product of all fourth roots of unity.
Question 14
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Find the sum of all cube roots of unity.
Question 15
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Which sixth roots of unity are also cube roots of unity?
Question 16
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For which integers \(k\) with \(0\le k\le7\) is \(e^{2\pi ik/8}\) a primitive eighth root of unity?
Question 17
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Find all fourth roots of unity that satisfy \(\operatorname{Im}(z)\ge0\).
Question 18
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A learner lists \(e^{2\pi ik/5}\) for every integer \(k\) as infinitely many fifth roots of unity. Explain the mistake.
Question 19
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Prove that every \(n\)-th root of unity has modulus \(1\).
Question 20
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Show that the product of two \(n\)-th roots of unity is again an \(n\)-th root of unity.