Proving Modulus of Rational Expression is Equal to 1

In summary, the problem is to prove or disprove the equation |\frac{e^{2i\theta} -2e^{i\theta} - 1}{e^{2i\theta} + 2e^{i\theta} -1}| = 1 and the suggested solution involves using the identities ei 2θ = cos(2θ) + i sin(2θ) and ei θ = cos(θ) + i sin(θ). The solution has been confirmed on the math stack exchange forum.
  • #1
Poopsilon
294
1

Homework Statement



Prove [tex]|\frac{e^{2i\theta} -2e^{i\theta} - 1}{e^{2i\theta} + 2e^{i\theta} -1}| = 1[/tex]

Homework Equations


The Attempt at a Solution



I feel like this should be fairly simple, anyone have any hints? Also this is just one step in an attempt to solve a much larger problem, so don't feel the need to be overly cryptic. Also that means I'm not entirely sure that it's true (but I think it is).
 
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  • #2
Poopsilon said:

Homework Statement



Prove [tex]|\frac{e^{2i\theta} -2e^{i\theta} - 1}{e^{2i\theta} + 2e^{i\theta} -1}| = 1[/tex]



Homework Equations





The Attempt at a Solution



I feel like this should be fairly simple, anyone have any hints? Also this is just one step in an attempt to solve a much larger problem, so don't feel the need to be overly cryptic. Also that means I'm not entirely sure that it's true (but I think it is).

I would use the facts that ei 2θ = cos(2θ) + i sin(2θ) and ei θ = cos(θ) + i sin(θ) and see where that took me.
 

1. What is the modulus of a rational expression?

The modulus of a rational expression is the absolute value of the expression, which means that any negative values in the expression are turned into positive values. It represents the distance of the expression from zero on a number line.

2. Why is it important to prove the modulus of a rational expression is equal to 1?

Proving that the modulus of a rational expression is equal to 1 is important because it helps to simplify and solve equations involving rational expressions. It also allows us to determine the behavior of the expression and its graph.

3. How do you prove that the modulus of a rational expression is equal to 1?

To prove that the modulus of a rational expression is equal to 1, we need to show that the numerator and denominator of the expression are equal in absolute value. This can be done by simplifying the expression and checking if the resulting numerator and denominator are equal.

4. What are some common techniques used to prove the modulus of a rational expression is equal to 1?

Some common techniques used to prove the modulus of a rational expression is equal to 1 include simplifying the expression, factoring the numerator and denominator, using the properties of absolute value, and using the definition of modulus.

5. Can the modulus of a rational expression ever be something other than 1?

Yes, the modulus of a rational expression can be something other than 1. It can be any positive value, depending on the expression. However, in order to prove that the modulus is equal to 1, we need to show that the numerator and denominator are equal in absolute value.

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