LOGIN/REGISTER
Please Wait...
It is currently Jul 29, 2010, 10:17 am
Post new topic Reply to topic  [ 14 posts ]  Share: Facebook
Message
Post Posted: May 01, 2007, 5:31 pm • # 1 


f is a continuous complex-valued function satisfying:

i) |f(z)| = |z|
ii) |f(z)-z| = |z|

Find f(f(f(2007)))

_________________
"I want to die in my sleep, like my grandfather. Not like the passengers in his car." :P
 
 
Post Posted: May 01, 2007, 6:23 pm • # 2 


Solution


Last edited by t0rajir0u on May 01, 2007, 7:02 pm, edited 3 times in total.
 
 
Post Posted: May 01, 2007, 6:28 pm • # 3 


why does a rotation of 60^\circ imply a third root of unity? wouldn't it be sixth root

_________________
"I want to die in my sleep, like my grandfather. Not like the passengers in his car." :P
 
 
Post Posted: May 01, 2007, 6:32 pm • # 4 


:maybe: It makes a triangle such that the angles are each 60^{\circ}.
Not a rotation though.

_________________
{Just Grok It} \mathbb{A}stronomy\mathbb{F}orum
dr^{2} = B\left(r\right)dt^{2}-A\left(r\right)dr^{2}-r^{2}d \theta^{2}-r^{2}\text{sin}^{2}\theta \ d \phi^{2}
 
 
Post Posted: May 01, 2007, 7:03 pm • # 5 


gotztahbeazn wrote:
why does a rotation of 60^\circ imply a third root of unity? wouldn't it be sixth root


Sorry, you're right. I've fixed it.

AstroPhys wrote:
:maybe: It makes a triangle such that the angles are each 60^{\circ}.
Not a rotation though.


One leg of this triangle is z, and the other is f(z). Hence f(z) is a 60^{\circ} rotation of z.

_________________
Annoying Precision (http://qchu.wordpress.com/)
 
 
Post Posted: May 01, 2007, 7:05 pm • # 6 


In that sense of the meaning of rotation, yes. :)

_________________
{Just Grok It} \mathbb{A}stronomy\mathbb{F}orum
dr^{2} = B\left(r\right)dt^{2}-A\left(r\right)dr^{2}-r^{2}d \theta^{2}-r^{2}\text{sin}^{2}\theta \ d \phi^{2}
 
 
Post Posted: May 01, 2007, 7:20 pm • # 7 


I really dont think you should post this a day before it is due, do your own homework! And even if you are just posting this because you thought it was interesting, you should still wait until after it is due.
 
 
Post Posted: May 01, 2007, 7:22 pm • # 8 


As far as I know the ARML coaches have always advocated kids working together and bouncing ideas off of each other.

_________________
"I want to die in my sleep, like my grandfather. Not like the passengers in his car." :P
 
 
Post Posted: May 01, 2007, 7:27 pm • # 9 


I think they advocate working together and bouncing ideas of eachother, as in with other members of the team or with kids from your school, not over the internet, and especially not on a site where people post full solutions to problems posed.

but perhaps I am wrong.
 
 
Post Posted: May 01, 2007, 7:32 pm • # 10 


heh it does you no good to post a question and copy the solution word for word and i agree that that would be cheating

however seeing as how i even corrected his solution, that shows that at least i understand his solution and i kno w where he's coming from with his solution and isn't that the point of hw?

anyways if the only reason you're posting this stuff is because you're worried that this might offset the proper team selection process, then take into account that the coaches consider your individual/power/relay performance during practice as well, in addition to AIME/AMC and ICTM stuff that you do

_________________
"I want to die in my sleep, like my grandfather. Not like the passengers in his car." :P
 
 
Post Posted: May 01, 2007, 7:32 pm • # 11 


Hey, kind of off topic, but I've completely lost my ARML schedule... the next practice is tomorrow? When are the others?

_________________
Say this ten times quickly: The product of the sums of squares is greater than the square of the sum of products!
 
 
Post Posted: May 01, 2007, 7:33 pm • # 12 


May 17th is the last one

_________________
"I want to die in my sleep, like my grandfather. Not like the passengers in his car." :P
 
 
Post Posted: May 01, 2007, 7:33 pm • # 13 


gotztahbeazn wrote:
May 17th is the last one


Ok, thanks. :)

_________________
Say this ten times quickly: The product of the sums of squares is greater than the square of the sum of products!
 
 
Post Posted: May 01, 2007, 10:09 pm • # 14 


NOOOO THEY HAVE MADE POST RATINGS NOOOOO

anyway...i came up with and posted an almost identical problem before...so w/e

i.e. let g(x)=[1/x]f(x)

_________________
-Alex
Altheman's Problem Column
 
 
Display posts from previous:  Sort by  

All times are UTC - 8 hours [ DST ]

Share: Facebook

Moderators: Peter, Intermediate Topics Moderators

Post new topic Reply to topic  [ 14 posts ] 

Login

Username:   Password:   Log me on automatically each visit  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum