(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Find all possible values of ##k## that make ##u = \frac{k+4i}{1+ki}## a purely real number.

2. Relevant equations

3. The attempt at a solution

I calculated the complex conjugate which was ##\frac{5k}{k^2+1} + \frac{4-k^2}{k^2+1}i##. So to prove this do I just solve ##\frac{4-k^2}{k^2+1}## = 0 for ##k##???

In this case ##k = \pm 2##. Thanks.

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# Homework Help: Purely Real Proof

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