Questions
Question 1
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State the principal argument interval used for a non-zero complex number \(z\).
Question 2
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Give one argument of the complex number \(3i\).
Question 3
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Find \(\operatorname{Arg}(-4)\).
Question 4
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Find \(\operatorname{Arg}(2-2i)\).
Question 5
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Find the principal argument of \(-3+3i\).
Question 6
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Find the principal argument of \(-5-5\sqrt{3}i\).
Question 7
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Write the general argument of \(1+i\) using an integer parameter.
Question 8
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Find the principal argument of \(\sqrt3-i\), giving the answer in radians.
Question 9
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A complex number has modulus \(6\) and principal argument \(-2\pi/3\). Find its Cartesian form.
Question 10
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Find all \(\theta\in[0,2\pi)\) such that \(\theta\) is an argument of \(-2i\).
Question 11
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Explain why \(\arg(z)\) is multi-valued but \(\operatorname{Arg}(z)\) is single-valued for \(z\ne0\).
Question 12
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A student says \(\operatorname{Arg}(-1-i)=5\pi/4\). Diagnose the error and give the correct principal argument.
Question 13
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Find \(\operatorname{Arg}\left((1+i)(-\sqrt3+i)\right)\) without first fully expanding the product.
Question 14
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Let \(z\) have \(\operatorname{Arg}(z)=3\pi/4\). Find the principal argument of \(-iz\).
Question 15
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For which real values of \(t\) is \(\operatorname{Arg}(t+i)=\pi/4\)?
Question 16
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For which real values of \(a\) does \(a-2i\) have principal argument \(-\pi/2\)?
Question 17
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Find all real \(x\) such that \(\operatorname{Arg}(x+xi)=3\pi/4\).
Question 18
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Prove that for any non-zero complex number \(z\), \(\operatorname{Arg}(-z)\) is obtained from \(\operatorname{Arg}(z)+\pi\) by adjusting into \((-\pi,\pi]\).
Question 19
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A non-zero complex number \(z\) satisfies \(\operatorname{Arg}(z)=\theta\). Determine \(\operatorname{Arg}(1/z)\) in terms of \(\theta\), including the endpoint case.
Question 20
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Show why \(\operatorname{Arg}(z_1z_2)\) is not always equal to \(\operatorname{Arg}(z_1)+\operatorname{Arg}(z_2)\), even though arguments add under multiplication.