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Hello can someone help I've been doing some exercises about complex numbers. But I am not really good at reading their graphic representations. Can you guys tell me if I did the exercise right, please?

The exercise: Let us consider the complex numbers z and w drawn in the Argand plane. What is the complex number u represented?

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  1. I choose -2z
  2. I choose the conjugate of z
  3. I choose z + w
  4. I choose 1/w
  5. I choose zw
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    $\begingroup$ Can you rewrite your question to be a bit more clear? Are you being presented choices? What is $z$, what is $w$? $\endgroup$ – scoopfaze Dec 2 '19 at 3:05
  • $\begingroup$ @scoopfaze I am sorry I hit the button submit with out adding the pictures $\endgroup$ – aita.kane Dec 2 '19 at 3:08
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    $\begingroup$ No worries, just trying to prevent downvotes $\endgroup$ – scoopfaze Dec 2 '19 at 3:10
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    $\begingroup$ First three look alright. I’m skeptical of the last two $\endgroup$ – scoopfaze Dec 2 '19 at 3:15
  • $\begingroup$ Thank you for your help. $\endgroup$ – aita.kane Dec 2 '19 at 3:30
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They are all correct. Pro-tip, when you multiply two complex numbers, you're adding their "angles" (with respect to the positive x-axis), so it makes sense that $zw$ is "between" $z$ and $w$.

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  • $\begingroup$ Thamk you for the tip and help. $\endgroup$ – aita.kane Dec 2 '19 at 3:29

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