Convert Fraction to Polar Form: H(F) = 5/(1+j2piF/10)

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Discussion Overview

The discussion revolves around converting the function H(F) = 5/(1+j2piF/10) into polar form, focusing on the magnitude and phase of the expression. Participants explore the mathematical steps involved in this conversion, including the treatment of the numerator and denominator separately.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant suggests that the phase is related to the term 2piF/10 but expresses uncertainty about its role in the denominator.
  • Another participant clarifies that the phase cannot be directly taken from the denominator and emphasizes the need to consider real and imaginary parts to find the angle using arctan.
  • There is a proposal to convert both the numerator and denominator to polar form separately before performing the division.
  • Participants discuss the importance of handling magnitudes and angles correctly, noting that the resultant angle is found by subtracting the denominator's angle from the numerator's angle.
  • One participant provides a partial result but questions how to incorporate the variable F into the final expression.
  • Another participant indicates that the expression can remain messy but still be correct, suggesting a specific form for the overall transfer function involving an exponential representation of the angle.

Areas of Agreement / Disagreement

Participants generally agree on the approach of separating the numerator and denominator for conversion to polar form, but there is some disagreement regarding the treatment of the phase and how to incorporate the variable F into the final expression. The discussion remains unresolved as participants explore different methods and interpretations.

Contextual Notes

There are limitations in the discussion regarding the clarity of terms used, such as "them" and "stuff," which may lead to confusion. Additionally, the mathematical steps for simplification and the exact form of the final expression are not fully resolved.

amiv4
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Homework Statement



H(F) = 5/(1+j2piF/10)

Rewrite in polar form, that is, in terms of magnitude and phase.

Homework Equations





The Attempt at a Solution



phase is the 2piF/10 but I'm not sure how I account for it being on the bottom of the fraction
 
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\frac{ A \angle \theta}{B \angle \phi} = \frac{A}{B} \angle \theta - \phialso "2piF/10" is not the phase, not even for the complex number in the denominator alone.

to find an angle, you think of it in terms of real and imaginary parts forming a right triangle on the unit circle. The angle is this:
\arctan\frac{Im(A \angle \theta)}{Re(A\angle \theta)}
 
Last edited:
So I should convert the top and bottom to polar separately and then divide them?
 
amiv4 said:
So I should convert the top and bottom to polar separately and then divide them?

we must be careful when you ask questions with so many undefined pronouns. If by them, you mean the magnitudes and if you meant "should i ... to find the resultant magnitude", then the answer is yes.

if you are talking about angles, however, the answer is no. you must subtract the denominator's angle from the numerator's angle to find the resultant angle.
 
Last edited:
k this is what i got

5\angle0/1.18\angle32.14

but idk where the F goes
 
amiv4 said:
k this is what i got

5\angle0/1.18\angle32.14

but idk where the F goes

the f remains symbolically.

for example, the magnitude of the bottom vector is:
\sqrt{1^2 + (\frac{2piF}{10})^2}
 
and then I would do the arctan of those two things to get the angle, but I don't see how they are going to simplify. Cuz I have to use this answer. Is there a way I could get the answer into a form similar to this H(F)=|5F| exp(-jpiF/10)
 
amiv4 said:
and then I would do the arctan of those two things to get the angle, but I don't see how they are going to simplify. Cuz I have to use this answer. Is there a way I could get the answer into a form similar to this H(F)=|5F| exp(-jpiF/10)

it doesn't need to simplify. it will be messy but correct. as for putting it in the form you've specified:

A \angle \theta = Ae^{j\theta}
and your theta for the overall transfer function will be:
\theta = -\arctan \frac{\pi F}{5}

the negative comes from 0 - stuff
 

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