MHB Complex Conjugates/Proof by Induction

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The discussion focuses on proving by induction that the conjugate of the product of complex numbers g1, g2, ..., gm equals the product of their conjugates. The user has successfully proven the case for m = 2 and is now seeking assistance for the inductive step, transitioning from m = n to m = n + 1. A suggested approach involves assuming the statement holds for m = n and demonstrating that it also holds for m = n + 1 by using the previously established result for m = 2. The explanation clarifies the process, leading to a successful conclusion of the proof. This method effectively utilizes the properties of complex conjugates to complete the induction.
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So I am having a bit of trouble with a proof by induction that I need to write. The problem is to prove that the conjugate of the product g1 * ... * gm equals the product of the conjugates of g1 ... gm. This is for g1 ... gm complex numbers.

I have proven this for m = 2, by simple calculation of the conjugates. Now I need to prove that if this is true for m = n then it is true for m = n + 1.

I appreciate any help you can offer, thank you.
 
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gucci said:
So I am having a bit of trouble with a proof by induction that I need to write. The problem is to prove that the conjugate of the product g1 * ... * gm equals the product of the conjugates of g1 ... gm. This is for g1 ... gm complex numbers.

I have proven this for m = 2, by simple calculation of the conjugates. Now I need to prove that if this is true for m = n then it is true for m = n + 1.

I appreciate any help you can offer, thank you.

If you showed that $\overline{g_1g_2}=\overline{g_1}\cdot \overline{g_2}$, and then assume that $\overline{g_1g_2\cdots g_n} = \overline{g_1}\cdot\overline{g_2}\cdots \overline{g_n}$, then it follows that
\[\overline{g_1g_2\cdots g_ng_{n+1}} = \overline{(g_1g_2\cdots g_n) g_{n+1}}\]
Let's define $g_1g_2\cdots g_n=z$. Then we're left with $\overline{z g_{n+1}}$, and we know from the $m=2$ case that this is the same as $\overline{z}\cdot\overline{g_{n+1}}$. Now rewrite this as $\overline{g_1g_2\cdots g_n}\cdot \overline{g_{n+1}}$ and apply the inductive hypothesis to finish the problem.

Does this make sense?
 
Thanks so much man, that really cleared it up for me!
 
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