FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Science and Technology » Physics
Quadratic equavasion
Post new topic   Reply to topic Page 1 of 1 [2 Posts] View previous topic :: View next topic
Author Message
tadchem
science forum Guru


Joined: 03 May 2005
Posts: 1348

PostPosted: Wed Jul 19, 2006 10:07 pm    Post subject: Re: Quadratic equavasion Reply with quote

Sergey wrote:
Quote:
I'm saving mutex into window registry for one of my programs, and I am
encrypting it using a simple quadratic equation. Such as y = x^2+20x, where
x is a value of a character (41 through 90), and y is a number I get which I
will store. Now, I was in college just about 4 or 3 years ago, or something
like that, work and all is turning me into moron. How do I solve for x? So
that I can decrypt this back into the character.

y=x^2+20x

x=?

The quadratic formula:

If

0 = a*x^2 + b*x + c

then

x = [ - b +/- SQRT( b^2 - 4 * a * c)] / (2 * a)

(you get 2 answers for the price of one:

x = [ - b + SQRT( b^2 - 4 * a * c)] / (2 * a)

and

x = [ - b - SQRT( b^2 - 4 * a * c)] / (2 * a)


In your case, a = 1, b = 20, c = - y

HTH

Tom Davidson
Richmond, VA
Back to top
Sergey
science forum beginner


Joined: 19 Jul 2006
Posts: 2

PostPosted: Wed Jul 19, 2006 7:10 pm    Post subject: Quadratic equavasion Reply with quote

I'm saving mutex into window registry for one of my programs, and I am
encrypting it using a simple quadratic equation. Such as y = x^2+20x, where
x is a value of a character (41 through 90), and y is a number I get which I
will store. Now, I was in college just about 4 or 3 years ago, or something
like that, work and all is turning me into moron. How do I solve for x? So
that I can decrypt this back into the character.

y=x^2+20x

x=?
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 1 of 1 [2 Posts] View previous topic :: View next topic
The time now is Mon Dec 18, 2017 2:43 pm | All times are GMT
Forum index » Science and Technology » Physics
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Quadratic elements of GF(p^n) Dhandapani Math 6 Fri Jul 14, 2006 9:45 am
No new posts Quadratic eigenvalue problem rjfmv Math 4 Wed Jul 12, 2006 4:54 pm
No new posts Quadratic eigenvalue problem rjfmv Symbolic 1 Wed Jul 12, 2006 4:50 pm
No new posts Diagonalizing a quadratic form Grothendieck-Hirzebruch Math 1 Wed Jul 05, 2006 10:22 am
No new posts Methods for solving quadratic equations Dave L. Renfro Math 0 Fri Jun 09, 2006 4:16 pm

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Electronics forum |  Medicine forum |  Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums  |  send newsletters
 


Powered by phpBB © 2001, 2005 phpBB Group
[ Time: 0.0770s ][ Queries: 20 (0.0625s) ][ GZIP on - Debug on ]