Find Formula for z in Complex Quadratic Equation

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SUMMARY

The discussion focuses on finding a formula for the complex variable z in the equation a*z - b*conj(z) + c = 0, where a, b, and c are complex constants. The initial attempt incorrectly applies the quadratic formula after multiplying the equation by z. The correct approach involves taking the complex conjugate of the original equation, leading to a system of two equations that can be solved simultaneously for z and conj(z).

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Homework Statement



consider

[tex]a*z - b*conj(z) + c = 0[/tex]

where a,b,c are unknown complex constants.

find a formula for z in terms of a, b, c

answer should be in the form "z = ..." where the ... does not contain any z or conj(z)

Homework Equations



I multiply the whole equation by z

[tex]z*(a*z - b*conj(z) + c) = 0[/tex]

=

[tex]a*z^2 - b*z^2 + c*z) = 0[/tex]

=

[tex](a - b)*z^2 + c*z = 0[/tex]

using the quadratic formula

[tex]z = \frac {-c \frac {+}{-} \sqrt{c^2}}{2*(a-b)}[/tex]
is this correct?

thanks!

The Attempt at a Solution

 
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No, [itex]z\overline{z}=|z|^2\neq z^2[/itex] in general.

Instead, take the complex conjugate of both sides of your original equation. That will give you two equations and two unknowns ([itex]z[/itex] and [itex]\overline{z}[/itex]) which you should know how to solve.
 

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