Why Must ##\mu_1, \mu_2## = ##\mu_1^*, \mu_2^*##? Parametric Resonance

In summary, the question is asking why ##\mu_1, \mu_2## must be the same as ##\mu_1^*, \mu_2^*##. It can be shown that if ##\mu_1\mu_2 = \mu_1^*\mu_2^*## and ##\mu_1+\mu_2 = \mu_1^*+\mu_2^*##, then ##\mu_1, \mu_2## are the same as ##\mu_1^*, \mu_2^*##. This can be proven by taking the complex conjugate of (27.5) which results in $$\mu_1\mu
  • #1
arpon
235
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pf.png

Why ##\mu_1, \mu_2## must be the same as ##\mu_1^*, \mu_2^*## ?

What I thought is : If ##\mu_1\mu_2 = \mu_1^*\mu_2^*## and ##\mu_1+\mu_2 = \mu_1^*+\mu_2^*##, then ##\mu_1, \mu_2## are the same as ##\mu_1^*, \mu_2^*##

It can be shown by taking the complex conjugate of (27.5) that $$\mu_1\mu_2 = \mu_1^*\mu_2^*=1$$
Now it is to be proven that ##\mu_1+\mu_2 = \mu_1^*+\mu_2^*##.
Any help would be appreciated.
 
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  • #2
If u1 = (a + bi) and u2 = (c + di), then you can write (a + bi)(c + di) = 1. Expanding it, you get:

ac + adi + bci – bd = 1. Rearrange as (ac – bd) + i(ad + bc) = 1. So (ac – bd) = 1, and (ad + bc) = 0. You may be able to get a starting point from that. If possible, I will try to come back and revisit this.
 
  • #3
scottdave said:
If u1 = (a + bi) and u2 = (c + di), then you can write (a + bi)(c + di) = 1. Expanding it, you get:

ac + adi + bci – bd = 1. Rearrange as (ac – bd) + i(ad + bc) = 1. So (ac – bd) = 1, and (ad + bc) = 0. You may be able to get a starting point from that. If possible, I will try to come back and revisit this.
Thanks for your help. But still could not get it.
 

1. Why do the parameters ##\mu_1## and ##\mu_2## have to be equal to ##\mu_1^*## and ##\mu_2^*## in parametric resonance?

In parametric resonance, the parameters ##\mu_1## and ##\mu_2## represent the frequencies of the external driving forces applied to the system. In order for resonance to occur, the system needs to respond strongly to these external forces at a specific frequency. By setting ##\mu_1## and ##\mu_2## equal to ##\mu_1^*## and ##\mu_2^*##, the system is able to match the frequency of the external driving forces, resulting in a resonant response.

2. What is the significance of ##\mu_1^*## and ##\mu_2^*## in parametric resonance?

##\mu_1^*## and ##\mu_2^*## represent the critical values of the parameters at which parametric resonance occurs. These values are determined by the properties of the system and the external driving forces, and are essential for achieving resonance. If the parameters deviate from these critical values, the system may not exhibit resonance.

3. How does parametric resonance affect the stability of a system?

Parametric resonance can lead to instability in a system if the external driving forces are too strong. This can cause the system to oscillate at a larger amplitude, potentially leading to damage or failure. However, when properly controlled, parametric resonance can also enhance stability by providing a way to amplify small signals and maintain a desired frequency of oscillation.

4. Can parametric resonance be observed in different types of systems?

Yes, parametric resonance can occur in a variety of systems, including mechanical, electrical, and biological systems. As long as there are external driving forces acting on the system and the parameters can be controlled, parametric resonance can be observed.

5. How is parametric resonance different from other types of resonance?

Parametric resonance is a specific type of resonance that occurs when the parameters of a system are periodically varied. Other types of resonance, such as forced resonance, involve a constant external force acting on the system. Additionally, parametric resonance can result in a larger amplitude response compared to other types of resonance.

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