
#1
Sep2510, 02:54 AM

PF Gold
P: 2,551

You can't really do anything with them since they're not real. Did mathematicians come up with it to give students some junk study material to bulk up math?




#2
Sep2510, 03:14 AM

HW Helper
P: 3,436

By the way, it is imaginary  not imagery  numbers I've heard that complex numbers help in quite a lot of aspects in the real world  although I haven't personally experienced them as of yet. They are imaginary numbers, but their use solves real problems. We can use imaginary numbers to convert multiples of cos and sin into powers of cos and sin instead. For example cos(2x)=2cos^{2}x1. Of course there are other ways besides using complex numbers to give the same result, but complex numbers can make things much easier. Same goes with some integration, and many others. Ages ago people believed that negative numbers were useless too, they had no physical significance because mass, distance, volume etc. are all positive. They had no use for them, but as you know we have found many uses for them. Thinking about it, most real world problems can be solved without negative numbers but we use these negative numbers to make things more simple. Rather than saying 2km forward and 3km backward, we use positive to describe forward and negative to describe backwards. But then again I could just be wrong and negative numbers were invented by mathematicians just like the complex numbers were to bombard students with more useless stuff to fill their time with 



#3
Sep2510, 03:39 AM

PF Gold
P: 2,551

Anyway, it's just my first runup with them...and it seems likely they have no use... just wanted to find out if that's the case...which it seems to be! 



#4
Sep2510, 04:22 AM

P: 4,513

What's the point of imagery numbers?
"What's the point of imagery numbers?"
What's the point of 'zero'? 



#5
Sep2510, 05:02 AM

P: 1,057

There is an association which invents new stuff just to annoy student.... ah... just kidding.
Complex numbers are incredibly important in maths and physics. With complex numbers many integrals are easily solved. Complex numbers and the Fourier transform help to solve differential equations which are basis of just everything in the real world. The equalizer on your stereo that shows the strength of the individual sound frequencies uses complex numbers to do the calculation. In physics all of quantum mechanics is based on complex numbers so they are the reason why you have all the electronic high tech equipment. In fact, you will (have?) learn(ed) at school that electric circuits are best handled with complex numbers. BTW: Search for complex numbers (and maybe "fluid dynamics") on this forum. There has been an extensive thread before. 



#6
Sep2510, 05:02 AM

PF Gold
P: 2,551

The point of zero is to indicate nothing. But...that still doesn't answer my question. 



#7
Sep2510, 05:46 AM

Emeritus
Sci Advisor
PF Gold
P: 16,101

Complex numbers were originally invented because the solution method to find the real roots of the cubic equation involved taking square roots of negative numbers. Subsequently, they have been found to have better algebraic, geometric, and analytical properties than the real numbers. Therefore, even if you are only asking questions about real numbers, they still often come into play because they make it easier to answer the question. Since people like physics, I'll point out examples of their utility in that field:




#8
Sep2510, 09:07 AM

Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 38,881

Historically, a major impetus for developing complex numbers ("imaginary numbers" are a subset) was Cardano's formula for solving cubic equations. It involves taking the third root of a square root of combinations of the coefficients. There are cases in which a cubic equation has real roots but using Cardano's formula to find those roots requires taking the square root of a negative number. The imaginary numbers cancel out in the end but are required in the formula.




#9
Sep2510, 09:12 AM

P: 1,057

But don't worry, Dory. Currently the studentoccupationagency is working on Surreal Numbers
http://en.wikipedia.org/wiki/Surreal_number which are even more complicating. So as soon as you grasp complex numbers there is more to come :D 



#10
Sep2510, 11:56 AM

P: 459

Go here
http://www.bbc.co.uk/programmes/b006qykl And click on the listen now button it should be available till next Tuesday. 



#11
Sep2510, 02:37 PM

P: 474

Then the programme is available permanently in the archive http://www.bbc.co.uk/radio4/features...rchive/science




#12
Sep2510, 03:59 PM

P: 2,258

strictly speaking a number only has magnitude.
A number with magnitude and direction is actually an ordered pair of numbers. There are many fields that use ordered pairs of numbers. The field of complex numbers is just one. After you learn about complex numbers then you can move on to quaternions. They are used in rotations or something like that. (I am using the word 'field' loosely here) 



#13
Sep2510, 04:25 PM

Emeritus
Sci Advisor
PF Gold
P: 16,101

Many prefer to use the a meaning appropriate to the situation, rather than adopt some dogmatic principle. (Also, don't confuse the analysis with the original object of study!) 



#14
Sep2510, 05:24 PM

HW Helper
Thanks
PF Gold
P: 7,197

"There's nothing imaginary about complex numbers" interesting. See: http://math.asu.edu/~kurtz/complex.html 



#15
Sep2610, 12:48 AM

HW Helper
P: 3,436





#16
Sep2610, 01:16 AM

P: 256





#17
Sep2610, 10:42 PM

P: 617





#18
Sep2710, 12:54 AM

P: 326

negative square root of 1
sorry, instantly had an answer for once o_o 


Register to reply 
Related Discussions  
page numbers in power point  Computers  2  
how many numbers to describe a point in space in GR?  Special & General Relativity  10  
Fixed Point Numbers  Programming & Computer Science  6  
The size of the sun using pinhole imagery  General Physics  4  
3D(?) Laser Imagery  General Physics  12 