Complex Exponent Rules and Misconceptions

  • Context: Undergrad 
  • Thread starter Thread starter Dark Fire
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the rules of complex exponentiation, particularly focusing on the expression (i*i*i*i) raised to various powers. Participants explore the implications of these rules, comparing them to real number exponentiation, and express their thoughts on the differences and misconceptions that arise when dealing with complex numbers.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that (i*i*i*i)^x equals 1 for any x, leading to the conclusion that (i*i) should equal 1, which contradicts the definition of i as the square root of -1.
  • Another participant points out that 1^0.25 has multiple solutions (1, -1, i, -i), which complicates the initial claim.
  • A participant expresses confusion over the transition from (i*i*i*i) to (i*i) in the context of exponentiation, questioning the validity of the steps taken.
  • Some participants argue that the laws of exponentiation apply differently to complex numbers compared to real numbers, emphasizing that (ab)^x is not necessarily true for complex values of a and b.
  • One participant reflects on their personal struggles with mathematics and how this affects their understanding of the topic, indicating a philosophical approach to the differences between real and complex numbers.
  • There is a discussion about the misconception that raising a number to a power can simplify the expression in a way that removes factors, particularly in the context of complex numbers.

Areas of Agreement / Disagreement

Participants express differing views on the application of exponentiation rules to complex numbers, with no consensus reached on the validity of the initial claims or the interpretations of the results.

Contextual Notes

Participants highlight the importance of understanding the definitions and properties of complex numbers, as well as the limitations of applying real number rules to complex exponentiation. Some mathematical steps remain unresolved, and assumptions about the behavior of exponentiation in complex contexts are questioned.

Who May Find This Useful

This discussion may be of interest to individuals exploring the differences between real and complex number systems, particularly in the context of exponentiation and mathematical reasoning.

Dark Fire
Messages
40
Reaction score
0
http://www.google.com/search?hl=com&q=(i*i*i*i)^0.3928".
(i*i*i*i)^x=1
Where x is any number
So:
(i*i*i*i)=1
(i*i*i*i)^0.25=1^0.25
(i*i)=1
But in default (i*i)=-1
So:
1=-1

Therefor (i*i*i*i)^0.25≠(i*i)
Which I find quite funny, weird, and interesting, since you can usually just put ^x numbers down when using root, like:
(3^3)=27
(3^3)^0.5=(3^2)=9

Any comments?
 
Last edited by a moderator:
Physics news on Phys.org
Dark Fire said:
http://www.google.com/search?hl=com&q=(i*i*i*i)^0.3928".
(i*i*i*i)^x=1
Where x is any number
So:
(i*i*i*i)=1
(i*i*i*i)^0.25=1^0.25
(i*i)=1
But in default (i*i)=-1
So:
1=-1

Therefor (i*i*i*i)^0.25≠(i*i)
Which I find quite funny, weird, and interesting, since you can usually just put ^x numbers down when using root, like:
(3^3)=27
(3^3)^0.5=(3^2)=9

Any comments?


First be careful, 1^0.25 has 4 solutions!

1, -1, i, and -i. if you raise either one of them to the 4th power you end up with 1.

Secondly, I have no idea how you get from the second to the third line(in the quote below), it just does not follow.

"So:
(i*i*i*i)=1
(i*i*i*i)^0.25=1^0.25
(i*i)=1"
 
Last edited by a moderator:
(i*i*i*i)=1 //Default
(i*i*i*i)^0.25=1^0.25 //Multiplied by itself by 0.25 on both side of equation
(i*i*i*i)^0.25=(i*i) //By default, this would be the answer with real numbers
i^0.25=1 //Most relevant
(i*i)=1 //Done

Whole point was with real numbers this works:
(3^3)^0.5=9
(3^3)^0.5=(3^2) //It's multiplied with itself one time less: 3*3*3 to 3*3
(3)^2=3*3
3*3=9

So this function works with real numbers:
(3*3*3)^0.5=(3*3)
But it doesn't work with complex/imaginary numbers:
(i*i*i*i)^0.5≠(i*i*i)

I'm just a teenager that stopped paying attention to school due to great problems at home and similar after 3rd-4th grade, and now that I got a lot of spare time, I'm just philosophizing.
This isn't some revolutionary piece of mathematical code, just a short philosophy of the difference between real numbers and complex/imaginary numbers.

Edit: Just figured I'm wrong, we were taught that (numbers) are always calculated first, but I guess ^ is an exception, because (3*3)^0.5=(sqrt 3 * sqrt 3), not (3*3=sqrt 9).
 
Last edited:
In general, the "law" axbx= (ab)x is true for real values of a and b, not complex values.
 
HallsofIvy said:
In general, the "law" axbx= (ab)x is true for real values of a and b, not complex values.

Yes, that was my philosophy.
Thank you for confirming.
 
Dark Fire said:
(i*i*i*i)^0.25=(i*i) //By default, this would be the answer with real numbers

I'm not sure that I understand where that is coming from...

Dark Fire said:
Whole point was with real numbers this works:
(3^3)^0.5=9
(3^3)^0.5=(3^2) //It's multiplied with itself one time less: 3*3*3 to 3*3
(3)^2=3*3
3*3=9

(3*3*3)^0.5 = 3^(3/2) = (3^0.5)*(3^0.5)*(3^0.5) = 3*(3^0.5) = 5.19615242, does it not?
 
Dark Fire said:
(i*i)=1

No, i*i = -1. That is the definition of i.
 
Dark Fire said:
(i*i*i*i)=1 //Default
(i*i*i*i)^0.25=1^0.25 //Multiplied by itself by 0.25 on both side of equation
(i*i*i*i)^0.25=(i*i) //By default, this would be the answer with real numbers
i^0.25=1 //Most relevant
(i*i)=1 //Done
That wouldn't even work if i was a real number. What you most likely mean is,
(i*i*i*i)^0.5=(i*i)

Whole point was with real numbers this works:
(3^3)^0.5=9
(3^3)^0.5=(3^2) //It's multiplied with itself one time less: 3*3*3 to 3*3
(3)^2=3*3
3*3=9
No, it doesn't. Try doing 27^0.5 on your calculator. I get something like 5.2. In general:
(a^b)^c = a^(bc)
For real numbers, so your example should be.
(3^4)^0.5=9

You somehow seem to think that ^0.5 will remove one factor, but that isn't the case. You should review the basic rules for real exponentiation before you get started on complex.
 
Dark Fire said:
http://www.google.com/search?hl=com&q=(i*i*i*i)^0.3928".
(i*i*i*i)=1
(i*i*i*i)^0.25=1^0.25
(i*i)=1

If they were REAL numbers, you'd have used the one of the exponetial laws wrong, simple math. So, exteneded the sum should look something like this:

(i^4) = 1
(i^4)^0.25=1^0.25
4*0.25=1
i=1^0.25

and as Diffy said, 1^0.25 has a few possibilities. So it would be one of those, most likely being i.

Which I find quite funny, weird, and interesting, since you can usually just put ^x numbers down when using root, like:
(3^3)=27
(3^3)^0.5=(3^2)=9

Once again, when there's a power outside the brackets, you multiply it by the one in the brackets. So what you're really doing is this:

(3^3)=27
(3^3)^0.5=27^0.5
3^1.5=5.19615.. etc.

The proper way of doing what you wanted to do with the threes would be this:

(3^3)=27
(3^3)^2/3=27^2/3
3^2=9
 
Last edited by a moderator:
  • #10
gunch said:
You somehow seem to think that ^0.5 will remove one factor, but that isn't the case. You should review the basic rules for real exponentiation before you get started on complex.
I'm a philosopher, not a mathematician.
Quite sad that is, since I presumably should technically have some potential, due to the fact that I got an IQ of above 130 (excluding social intelligence), and been considering an education within physics, but I've figured mathematics is just pissing me off, and everyone seem to be of greater understanding relative to time, than me, so it's not worth it.

PS: yes, I thought it would remove one factor, since I temporary relayed on the fact that ^0.5 removes one factor when the exponent is equal to 2 (2 -> 1).
Kaimyn is right, I'm just.. not very clear in my thinking now a'days..
Too much on the computer, prioritizing only the easiest solutions/shortcuts, and haven't been doing mathematics for years, also only knowing the very very basics of it, due to lack of ability to concentrate @ school.

Thanks for replies anyways.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
1
Views
2K
  • · Replies 0 ·
Replies
0
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 29 ·
Replies
29
Views
2K