Complex Conjugates/Proof by Induction

In summary, the conversation discusses a proof by induction to show that the conjugate of a product of complex numbers is equal to the product of their conjugates. The speaker has proven this for m=2 and is now working on proving it for m=n+1, using the inductive hypothesis. They seek clarification and the other person provides a helpful explanation.
  • #1
gucci1
13
0
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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  • #2
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?
 
  • #3
Thanks so much man, that really cleared it up for me!
 

Related to Complex Conjugates/Proof by Induction

1. What are complex conjugates?

Complex conjugates are pairs of complex numbers that have the same real part but opposite imaginary parts. For example, the complex conjugates of 2+3i are 2-3i and vice versa.

2. Why are complex conjugates important?

Complex conjugates are important in a variety of applications, including solving equations involving complex numbers, simplifying expressions, and solving differential equations. They also have important applications in physics, engineering, and other fields.

3. What is the proof by induction method?

Proof by induction is a mathematical technique used to prove statements about a set of numbers or objects that has an infinite number of elements. It involves showing that a statement is true for a base case, and then proving that if the statement is true for one element, it is also true for the next element in the set.

4. How is proof by induction used to prove properties of complex conjugates?

To prove properties of complex conjugates, we can use proof by induction to show that a statement about one complex conjugate is true, and then use the fact that complex conjugates have the same real parts to show that the statement is also true for the other conjugate.

5. Can proof by induction be used to prove all properties of complex conjugates?

No, proof by induction is only one method of proving properties of complex conjugates. Other methods, such as direct proof or proof by contradiction, may also be used depending on the specific property being proven.

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