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Jan
1
comment Show $1+x+(x^2/2!)+ \cdots + (x^n/n!)=0$ has no rational solutions for all $n>1$.
you should withdraw the acceptance of this answer. It does not make sense to accept an unvalid answer: The question is now a question with an accepted answer and so nobody who looks for open questions to answer will find it.
Jan
1
comment Show $1+x+(x^2/2!)+ \cdots + (x^n/n!)=0$ has no rational solutions for all $n>1$.
How does the solution that you accepted help you. It stopped there where you already were ($q=\pm 1, p \mid n!$)?
Jan
1
comment Prime Number Sieve using LCM Function
The $b_n$ are actually two independent sequences: $$\\ b_{n}=b_{n-1}+\text{lcm}(2n-1,b_{n-1}), n \ge 2, b_1 =2, \text{former even indexes} \\ b_{n}=b_{n-1}+\text{lcm}(2n-2,b_{n-1}), n \ge 2, b_1=2, \text{former odd indexes} $$ a similar sequence: $$b_n = b_{n-1} + \text{lcm}(n,b_{n-1}), n\ge 2, b_1=1$$ oeis.org/A135504 , oeis.org/A217663
Dec
31
comment Counterexample to disprove that $P(A-B) = P(A) - P(B)$?
It is always $$P(A-B) \ne P(A) - P(B)$$ because the lhs contains the empty set and the rhs does not.
Dec
31
comment A generalized derivative
I think it should be $\alpha f(x)^{\alpha-1}\cdot f'(x)\left|\right._{x=x_0}$
Dec
31
comment How many combinations can a group of n people form?
@Kloar: Yopu are absolutely right, I missed this. I will update the answer.
Dec
31
comment Ratios with Ages
@Przemysław Scherwentke: On your homepage I think you want to say that English is not your mother tongue
Dec
30
comment How to put 9 pigs into 4 pens so that there are an odd number of pigs in each pen?
You should supply your code and try to convince us that it produces all possible solutions.
Dec
28
comment The game with countable amount of steps
if the angel makes the first move, he will loose even for k=1 because the devil will never remove the number from his box that the angel put in his box in the first move.
Dec
27
comment Convergence and Crash of a derivation (Chomsky)
and which work of Chomsky are you citing?
Dec
27
comment Examples of magmas with all their elements idempotents
what did you try?
Dec
27
comment Filters and Convergence
your definition in the comment is blunder, can you correct it. You should add the correct definition to the post
Dec
24
comment Find the inverse function of $\log_{\sqrt{4-x^2} } \left(x^3+5x^2-x \right)$
The logarithm to base $\sqrt{4-x^2}$ notation can be avoided but I would be surprised if there is an inverse that can be composed of elementary functions $$\begin{array}\\ f(x) &=& \log_{\sqrt{4-x^2} } \left(x^3+5x^2-x \right)\\ &=&\frac{\log(x^3+5x^2-x)}{\log{ \sqrt{4-x^2}}} \\ &=& 2\frac{\log(x)+\log(x-\frac{-5-\sqrt{29}}{2})+\log(x-\frac{-5+\sqrt{29}}{2})}{ \log(2-x)+\log(2+x)} \end{array}$$
Dec
23
comment Find the inverse function of $\log_{\sqrt{4-x^2} } \left(x^3+5x^2-x \right)$
What did you try and what is function 3?
Dec
23
comment systems of 2 equations in 2 variables
This is not a system of linear equation!
Dec
22
comment Knapsack problem NP-complete
Instead of "Let $A=\{a_1, a_2, \dots , a_m\}$ and $A_1, A_2, \dots , A_{\lambda}$ be the set and the subsets of an instance of the Exact Cover problem." I would prefer "Let $A_1, A_2, \dots , A_{\lambda}$ a cover of the set $A=\{a_1, a_2, \dots , a_m\}$. We want to decide if it contains an exact cover." But I am not a native speaker. But the rest is ok as far as I can see
Dec
22
comment Knapsack problem NP-complete
the sentence "Let the set $A=\{a_1, a_2, \dots , a_m\}$ and the subsets $\{A_1, A_2, \dots , A_{\lambda} \}$ an instance of the Exact Cover problem." does not have a verb.
Dec
22
comment Knapsack problem NP-complete
The exponent is $(r-1)$ $$i_j=\sum_{r=1}^{\lambda}e_{jr}(\lambda+1)^{r-1}$$
Dec
21
comment Knapsack problem NP-complete
You should try to convert a cover of a set to a knapsack, e.g. en.wikipedia.org/wiki/Exact_cover#Detailed_example
Dec
18
comment Prove that $a^ab^bc^c\ge (abc)^{(a+b+c)/{3}}$
That was not intended as a help for you. you mentioned that the question was already posed but did not supply a link.