Reputation
7,031
Top tag
Next privilege 10,000 Rep.
Access moderator tools
Badges
7 28 91
Impact
~162k people reached

2d
comment Is it possible to find the criminal with graph-theoretic methods?
It seems that writing it the way I'm writing, there are solutions. See here.
2d
comment Is it possible to find the criminal with graph-theoretic methods?
You wrote $(D\lor\neg M)$ for "*It wasn't $D$; It was $M$*". I'm writing it differently: I'm writing $(\neg D\lor M)$ for it. Is there a problem with this?
2d
comment Is it possible to find the criminal with graph-theoretic methods?
There is one way to write a boolean expression to check that, isn't it? I'm just not sure if it would be: $$\neg d\land m\land \neg m\land \neg d\land d\land \neg g\land m\land M\land j\land \neg g$$ Or $$(\neg d\land m)\lor (\neg m\land \neg d)\lor (d\land \neg g)\lor (m\land M)\lor (j\land \neg g)$$
2d
comment Is it possible to find the criminal with graph-theoretic methods?
I changed it, but it was what I meant with: Knowing everyone told a lie, who was the criminal?.
2d
comment Is it possible to find the criminal with graph-theoretic methods?
No, each one told only one lie.
Aug
22
comment The method of exhaustion in tom apostol calculus vol $1$
You can skip this intro and keep reading it nonetheless. As you progress through the book, you may have developed more mathematical maturity. I tell you this because the first time I took this book, I knew very little mathematics and also found the introduction a little hard.
Aug
18
comment On the inner workings of induction?
Good, that's the spirit. When I read about induction, everything seemed to be connected and it made no sense. After some thought, I realized that induction is one thing that can be used to prove ideas in another ideologically feasible frameworks, such as graphs, semirings (in this case), etc.
Aug
18
comment On the inner workings of induction?
No, I'm not trying to prove it's right. I'm trying to understand what are the laws that forbid me of writing $f(k+1)= f(k)+(k+1)$. And I guess it has something to do with the semiring axioms.
Aug
18
comment On the inner workings of induction?
I mean, to write $f(k+1)$ as $f(k)+(k+1)$, I need to have the idea of equivalent rewriting, and I guess this idea comes from the semiring axioms.
Aug
18
comment On the inner workings of induction?
Why doesn't induction works on semirings? After all, we're dealing with $\Bbb{N}$, addition and multiplication. And it follows these axioms.
Aug
18
comment On the inner workings of induction?
@KittyL Yes. The weird thing is that using the first $5$ numbers of that sequence, it yields preciselly the formula of the sum of the first $n$ positive integers. I'm curious about why does it gives precisely $\cfrac{x(x+1)}{2}$ and not some other random formula. But I'll ask this on another ocasion.
Aug
18
comment On the inner workings of induction?
@whacka Yes. I've also looked for some easy sequence (sharing some of the first terms) on OEIS. But as I read Farrugia's article I mentioned in the text, I had to use it because seemed fun.
Aug
18
comment On the inner workings of induction?
Sorry, @whacka. We edited at the same time.
Aug
17
comment How do I prove this $\frac{dx^n}{dx}=nx^{n-1}$ is true for every $n\geq 1$ to convince my students?
@AndréNicolas That is the proof that is also given by Hairer/Wanner: Analysis by It's History. I guess that it's the less bureaucratic way to do it, since it rely only in the proof of the product rule, which is quite simple.
Aug
17
comment Why don't we start studying calculus via series instead of the calculus on finite expressions?
@ChristianBlatter I don't get it. What's the conclusion?
Aug
15
comment Why to include the $C$ in the formula for the distance in hyperbolic geometry?
@Blue Not yet. I thought I ought to know, mainly because there is an exercise on this page.
Aug
12
comment Does Temporal Logic have undecidable propositions?
According to Enya, only time can say that hardly decidable propositions are true of false. So, perhaps you're on the right track.
Aug
11
comment Can someone show me HOW to do this, I don't just want the answer
@user261310 What do you mean with "show"? The equation is solved for $n$ with applications of the field axioms. But I'm not sure if what you want is a deep explanation.
Aug
9
comment Why can't I use this shortcut here?
@Richard If you have $16x^2 = 64$ and in the next step you have $16^4$ in the right side, then you've exponentiated both sides to $4$. That is: $$[16x^2]^4 = [64]^4$$ Then it should be: $$16^4x^8 = 64^4$$
Aug
9
comment Solving equations with logarithmic exponent
What is $lg(x)$?