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Discrete Math

Anonymous Mon 05 Oct 15:32:24 2020 No.12195947 View Reply Original Report

Quoted By: >>12195989 >>12197452

I really need some help fellas.

This assignment as it has left me confused. It's a recursive algorithm and I'm supposed to find out the 5 first terms. However there's the variable "b" and "a" which have not been defined, and it makes me confused.

Have I done it correctly? If I have it seems to be way too easy, that's actually why I'm also unsure

Anonymous

Anonymous Mon 05 Oct 2020 15:43:51 No.12195989 Report

Quoted By: >>12195998

>>12195947
I didn't check your arithmetic, but yes, just expand out and simplify. It doesn't matter whether what a or b is here.

Anonymous

Anonymous Mon 05 Oct 2020 15:45:29 No.12195998 Report

Quoted By: >>12196004

>>12195989
cheers, I just think the answer looks so fucking stupid and nowhere in our book do we have undefined variables, oh well teachers can do wtf they want i suppose

Anonymous

Anonymous Mon 05 Oct 2020 15:48:50 No.12196004 Report

Quoted By: >>12196009

>>12195998
What do you mean "undefined variables?" It suffices to know that $a, b \in \mathbb{Z}$ or something similar. They're well defined, even if they don't use numerals as part of their name.

Anonymous

Anonymous Mon 05 Oct 2020 15:50:31 No.12196009 Report

Quoted By: >>12196014

>>12196004
i meant more like unassigned, my bad

Anonymous

Anonymous Mon 05 Oct 2020 15:52:46 No.12196014 Report

Quoted By: >>12196019

>>12196009
oh, you mean in a programming sense. Either way, you'll find that discrete, and really the pure math related to intro CS, asks that you really be comfortable with these numbers despite not knowing their value. This is particularly important when you start studying factoring and associated algorithms.

Anonymous

Anonymous Mon 05 Oct 2020 15:54:24 No.12196019 Report

Quoted By: >>12196036

>>12196014
yeah im actually kinda enjoying this course, it really shows the relationship between maths and programming, but we had a previous math course which was just high school math that I believe was a total waste of time

Anonymous

Anonymous Mon 05 Oct 2020 16:01:09 No.12196036 Report

Quoted By:

>>12196019
there's a lot of serious math in CS, and a lot of it is immediately useful for solving practical problems. I recommend doing Knuth's Concrete Mathematics if you wanna learn more, and looking up some courses on MIT opencourseware if you're interested in applications in CS.

When you're more comfortable with everything, here's a really cool paper about a simple way to get a really good pseudorandom number.
https://arxiv.org/abs/1203.5731
>had a previous math course which was just high school math that I believe was a total waste of time
yeah unfortunately a lot of intro CS is full of bullshit babysitting classes. The upper div stuff is cool if you go for the theory (complexity, algorithms) and systems (graphics processing, OS) though, as far as I'm concerned

Anonymous

Anonymous Mon 05 Oct 2020 20:18:09 No.12196967 Report

Quoted By: >>12196994 >>12197217 >>12197779

Guys, I have another question.
A number sequence, t(n), where n $\geq$ 1, is given by the following algorithm,

Function t(n):
1. If n = 1 (mod 2) then
1.1. t $\gets$ 3n+1
else
1.2. t $\gets$ n/2

a) Show that for all n there exists an m such that t(t(...t(n))) {m times} = 1

Any help would be appreciated

Anonymous

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Anonymous Mon 05 Oct 2020 20:25:33 No.12196994 Report

Quoted By:

>>12196967
Clever post anon, clever post.

Anonymous

Anonymous Mon 05 Oct 2020 21:25:55 No.12197217 Report

Quoted By:

>>12196967
I've found a mesmerizing solution but it's too long for this post

Anonymous

Anonymous Mon 05 Oct 2020 22:53:47 No.12197452 Report

Quoted By:

>>12195947
you can't find a or b without the initial condition

Anonymous

Anonymous Tue 06 Oct 2020 00:27:18 No.12197779 Report

Quoted By:

>>12196967
Only if you solve mine! Let the radical of x be defined as the multiple of distinct prime factors of x (rad(9)=3, rad(27)=3). Prove that for every positive real number ?, there exist only finitely many triples (a, b, c) of coprime positive integers, with a + b = c, such that c>rad(abc)^(1+?)

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