Complex numbers with an unknown, fraction equation not getting it right

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SUMMARY

The discussion centers on solving a complex number equation involving the variable z and the imaginary unit i. The initial solution provided, z = 2/(1 + i), was identified as unsimplified. The correct approach involves multiplying by the conjugate and correctly applying the properties of i, specifically that i^2 equals -1. The final solution is confirmed to be -1 + i, emphasizing the importance of careful algebraic manipulation in complex number equations.

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  • Familiarity with algebraic manipulation techniques
  • Knowledge of complex conjugates
  • Basic proficiency in handling imaginary units, specifically i
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  • Study the process of simplifying complex fractions
  • Learn about complex conjugates and their applications in algebra
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Femme_physics
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Attempt solution attached
Manual says the answers is -1 + i
 

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The solution you posted,
[tex]z = \frac{2}{1 + i}[/tex]
is not simplified. You know that you can multiply top and bottom by the conjugate, right? Even so, you still won't get the right answer.

EDIT: I think I found it. From the 2nd to 3rd line, on the RHS you have
[tex](2iz + 1)(1 - i) = 2iz - 2iz + 1 -i[/tex]
, which is wrong. It should be
[tex](2iz + 1)(1 - i) = 2iz - 2i^2 z + 1 - i[/tex]
.
 
Last edited:
Thanks for the great catch! :) I wasn't sure I even know how to solve these. Glad to see I didn't do anything horribly wrong. Apparently it's all about treating i and z like x and y, and if i ever gets to the power of 2, just turn into -1. Easy peasy :)

Appreciate you taking the time to spot my carelessness!
 

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