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Jan
16
comment Cubes differences and primality
I completed the prove, I hope there are no errors. But I can't see how that will help you to avoid trial an error. Can you explain this?
Jan
16
comment Cubes differences and primality
@Ross Millikan, thank's
Jan
12
comment Is there an intuitive explanation for $ x^2+y^2=7 z^2 $ doesn't have any integer solution?
I still I can't see where you use the fact that $x^2+y^2=z^2$ has infinite integer solutions.
Jan
12
comment Is there an intuitive explanation for $ x^2+y^2=7 z^2 $ doesn't have any integer solution?
That is neither a answer to the question ("Does this fact ...") nor does this give us a complete answer to the more usefull question: what are the integer solutions of the equation.
Jan
10
comment how can I prove that $\frac{\arctan x}{x }< 1$?
@enzolib: thanks, I added this to the answer.
Jan
9
comment How do I find which set of functions is linearly independent?
and how do you prove that all other are not linear dependent?
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
here is a more systematic technic math.stackexchange.com/a/544042/11206 but maybe much more than you want.
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
+1, but maybe incomprehensibly to the OP
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
$x({1^2}+1)-a(1^2-1)$ equals $2x$ and not ${x^2}-{a^2}+x+a$. As Hurkyl already noted, your attempt to create a common factor contains an error.
Jan
5
comment Find least possible number of factors
Where can I see that this is a multiple choice question?
Jan
5
comment Find least possible number of factors
Due to what constraint?
Jan
5
comment Find least possible number of factors
you are missing a lot of other cases you have to check
Jan
5
comment Find least possible number of factors
It would be nice if you can change it to a readable format using latex. I did the first few lines for you as an exapmle.
Jan
5
comment Find least possible number of factors
you cannot assume that $AB has exactly three prime factors. It is possible that it has only two or one prime factor.
Jan
5
comment Find $\lim_{n\to \infty}f_{n}(1)=?$
the functions until n=10: maxima-online.org/…
Jan
3
comment Three digit number $ABC$ with $ABC = A + B^2 + C^3$
I suppose the equation is wrong, because $ABC$ means $A\times B \times C$. The first trick is to write $$100A+10B+C=A+B^2+C^3$$
Jan
3
comment questions about probabilistic primality test
Which online Rabin-Miller test do you use? Can you provide the link?
Jan
3
comment How to show result in terms of $\pi$ in Mathcad?
@Rory Daulton: No, it is absolutely on topic to pose a question about Mathcad. If it is a question about Mathcad it does not make sense to change it in a question about anything else. I think the post is about symbolic calculation in Matchcad.
Jan
2
comment Is $1234567891011121314151617181920212223…$ an integer?
I modified the post you referenced becuase it is simply wrong to calll $123\ldots$ a number. Your question title is not posed wll, too. I changed your question tile too, because it contains the invalid assumption that this is a number.
Jan
2
comment The following is unclear to me:($f$ is the identical function) the inverse of $f: X\to X$ is not continuous(if the second space isnt discrete)
The OP contains its (valid) definition of a continous function, so you should write an answer according to this definition and not simply reproduce a standard proof