# Modular Function To A Matrix

3 replies to this topic

### #1 aaracena

aaracena

Newbie

• Members
• 4 posts

Posted 04 August 2004 - 03:09 PM

Hello,

I need that the result of a matrix multiplicacion can be affected by a modular function, for example, I will show a criptography exercise that use it:
(9 , 20 ) x
11 8
3 7 = (99 + 60, 72 + 140) = (159, 212)

thist result applying modulo 26 is = (3,4)

to this result, I need to applied a inversed matrix that multiplied with the computation above will give me the original number (9, 20), all using mod 26:

inverse
11 8
3 7 =

7 18
23 11

(3, 4) x
7 18
23 11 = (9, 20)

I need to do that with the classpad 300, somebody know do that?, thank you.

Amaury A.

pst.

I need calcutate the inverse and apply modular function to the result.

### #2 betoe

betoe

UCF Spanish Translator

• [Legends]
• 846 posts
• Gender:Male
• Interests:Electronics, SW development, automotive. Swim->bike->run

• Calculators:

Posted 19 August 2004 - 04:30 AM

Hi guys.

There are some photos with examples of what aaracena needs, he send it to me via email some days ago (sorry i was very busy) and now i hosted them on my site for you.

Photo 1
Photo 2

I will try to read it and analize it for try to help with this.

### #3 R00KIE

R00KIE

Casio Freak

• Members
• 155 posts
• Location:Portugal
• Interests:Electronics, games, programming

• Calculators:
HP49G ROM 1.24; CASIO CFX-9850GB PLUS;CASIO FX-6300G; CASIO FX-82TL

Posted 04 September 2004 - 09:11 PM

I don't know much about modular math but i took a look at your exercice and what i think you need to do is get the final matrix divide it by 26 (what you need) keep only the fractional part and the multiply it by 26.

In your calculator make all the steps you need and then just do the following to the resuting matrix

assume you have the result [99+60,72+140] => [159,212] in Mat A, then do

Frac ( Mat A*(1/26))*26 and you get [3,4]

i hope this helps

### #4 jlssoft

jlssoft

Newbie

• Validating
• 6 posts
• Location:Mor?n de la Frontera-Sevilla. Spain

• Calculators:

Posted 05 September 2004 - 08:52 AM

Me parece que lo que buscas est?s en mi p?gina personal. Mira aqu? (si no sabes espa?ol puedes pedirle ayuda a Betoe):
http://www.omerique....riptografia.htm
Espero que te sea de ayuda.
Saludos.

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users