How to calculate the magnitude of a function?

In summary, the task was to find the magnitude of a given function, G(w)=\frac{1}{j\omega\tau+1}. The equation for magnitude, S=\alpha+j\beta, was provided. The attempt at a solution involved carrying out the division, but resulted in an incorrect expression. The correct approach is to multiply the numerator and denominator by -j\omega\tau+1 and then take the magnitude using the provided equation. The magnitude of the numerator and denominator can be found by splitting them into real and imaginary parts and using the given magnitude equation. Dividing these magnitudes will give the desired result.
  • #1
seto6
251
0

Homework Statement


I have this function:

G(w)=[itex]\frac{1}{j\omega\tau+1}[/itex]
I want to find the magnitude

Homework Equations


S=[itex]\alpha[/itex]+j[itex]\beta[/itex]

magnitude(S)=[itex]\sqrt{[itex]\alpha[/itex]^{2}+[itex]\beta[/itex]^{2}}[/itex]3. The Attempt at a Solution [/b

What i did was carry out the division,

so i got
[itex]\frac{j\omega\tau-1}{-(j\omega+1)}[/itex]
then do i just split it into real and imaginary part and then take the magnitude using this?
S=[itex]\alpha[/itex]+j[itex]\beta[/itex]

magnitude(S)=[itex]\sqrt{[itex]\alpha[/itex]^{2}+[itex]\beta[/itex]^{2}}[/itex]

Can anyone help i am not so sure how to approach this?
 
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  • #2
seto6 said:
What i did was carry out the division,

so i got
[itex]\frac{j\omega\tau-1}{-(j\omega+1)}[/itex]

This is where you got it wrong. Try to multiply the numerator and the denominator of the original G(ω) by [itex] - j ω \tau + 1[/itex] and see what you get.
 
  • #3
Then, try and think what you had to multiply by the expression [itex]- j ω \tau + 1 [/itex] to get your answer.
 
  • #4
seto6 said:

Homework Statement


I have this function:

G(w)=[itex]\frac{1}{j\omega\tau+1}[/itex]
I want to find the magnitude

Homework Equations


S=[itex]\alpha[/itex]+j[itex]\beta[/itex]

magnitude(S)=[itex]\sqrt{[itex]\alpha[/itex]^{2}+[itex]\beta[/itex]^{2}}[/itex]


3. The Attempt at a Solution [/b

What i did was carry out the division,

so i got
[itex]\frac{j\omega\tau-1}{-(j\omega+1)}[/itex]
then do i just split it into real and imaginary part and then take the magnitude using this?
S=[itex]\alpha[/itex]+j[itex]\beta[/itex]

magnitude(S)=[itex]\sqrt{[itex]\alpha[/itex]^{2}+[itex]\beta[/itex]^{2}}[/itex]

Can anyone help i am not so sure how to approach this?


Failexam's suggestions are all you need to do. However, if you are going to use LaTeX, why not do it properly? Your expression for "magnitude(S)" is ugly; here is what it should look like: [itex]\text{magnitude}(S)=\sqrt{\alpha^2 + \beta^2}.[/itex] To get this, just remove the "inner" [i t e x]-[/i t e x] pairs; furthermore, if you want the word "magnitude" to appear in nice text font, just include it inside the [i t e x] command, but say \text{magnitude}.

RGV
 
  • #5
The magnitude of two vectors divided is the division of the magnitudes. What is the magnitude of the numerator? What is the magnitude of the denominator? What is the result of dividing those magnitudes?
 

1. What is the difference between magnitude and absolute value?

The magnitude of a function refers to its size or overall value, while the absolute value specifically refers to the distance of a number from zero on a number line. In other words, the absolute value is always positive, while the magnitude can be positive or negative.

2. How do I calculate the magnitude of a function?

To calculate the magnitude of a function, you can use the Pythagorean theorem, which states that the magnitude is equal to the square root of the sum of the squares of the function's components. Alternatively, you can use the absolute value function to find the distance from zero.

3. Can the magnitude of a function be negative?

Yes, the magnitude of a function can be negative if the function itself has a negative value. This is because the magnitude is a measure of the size of the function, not its positivity or negativity.

4. What is the significance of calculating the magnitude of a function?

Calculating the magnitude of a function can help us understand the overall size or strength of the function, which can be useful in various scientific and mathematical applications. For example, in physics, calculating the magnitude of a force can help determine its effect on an object.

5. Are there any limitations to calculating the magnitude of a function?

One limitation to calculating the magnitude of a function is that it does not take into account the direction of the function. This means that two functions with the same magnitude but different directions can have different effects or outcomes. Additionally, the concept of magnitude may not be applicable to all types of functions, such as complex numbers.

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