172 reputation
9
bio website hiddewieringa.nl
location Netherlands
age 20
visits member for 2 years, 4 months
seen 2 days ago

I am a PHP software developer, who likes scripting and solving Project Euler problems using Python (and sometimes C++ and Java).

Fan of coffee, computers and cycling.


Jun
16
comment Check for differentiability and limit in 0 of $f(x) = \sum_{n=5}^{+\infty}\frac{x\cdot \sqrt{n}}{n^2-x^2}$
Why don't you just fill in $0$ in $f(x)$? You can easily evaluate $\sum_{n=5}^\infty \frac{0 \cdot \sqrt{n}}{n^2 - 0^2}$.
Aug
15
comment Solving $x^2 \cdot y^2 + x^2 + y^2 = c^2$ with $x$, $y$, $c \in \mathbb{Z}^+$
I have read your answer, and I agree a lot. I am letting my mind go over it while I am sleeping, that always helps. The reduction of the range of $x$ is good, it should help. I hope though that something in the range of $10^{11}$ is computable.
Aug
15
comment Solving $x^2 \cdot y^2 + x^2 + y^2 = c^2$ with $x$, $y$, $c \in \mathbb{Z}^+$
I really don't understand what you are trying to do in your solutions. Maybe I am not mathematically educated enough. If it is really a solution to my problem, it would be nice if you could explain a little what you are doing.
Aug
15
comment Solving $x^2 \cdot y^2 + x^2 + y^2 = c^2$ with $x$, $y$, $c \in \mathbb{Z}^+$
@MarkBennet Thanks for the comment, I found that out already. I still require 25 minutes of computing power to calculate all the $(x, y)$ for $c \le 10^6$. $10^{10}$ is just not possible brute force.
Aug
15
asked Solving $x^2 \cdot y^2 + x^2 + y^2 = c^2$ with $x$, $y$, $c \in \mathbb{Z}^+$
Aug
11
awarded  Scholar
Aug
11
comment Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
That is a great answer, it gave me the push in the back to find the answer. Thanks a lot for your time.
Aug
11
accepted Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
Aug
11
comment Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
@MarkBennet I got that part covered. Thanks so far for all the input, I'm coming somewhere.
Aug
11
comment Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
Very right, this is what I am calculating. Editing the question.
Aug
11
revised Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
added 171 characters in body
Aug
11
asked Solving $\phi (n) < (n-1) \cdot \frac{15499}{94744} $
Mar
18
awarded  Citizen Patrol
Mar
14
revised How do we get the result of the summation $\sum\limits_{k=1}^n k \cdot 2^k$?
Added LaTeX to make the question more readable
Mar
14
suggested suggested edit on How do we get the result of the summation $\sum\limits_{k=1}^n k \cdot 2^k$?
Mar
14
awarded  Quorum
Mar
5
comment Pixel + Zoom geometry
What have you tried?
Feb
28
comment How to solve $\frac{dp}{dt}=t^2p-p+t^2-1$
$\int (t^2 -1)dt = \frac{1}{3} t^3 - t$. Typo probably.
Feb
20
comment Regular Expressions - alphabet $(a, b, c)$
Is this maybe a StackOverflow question? Please show what you need it for, and what you have tried so far.
Feb
20
comment Definition of asymptote
In infinity, the distance between the line and the asymptote is 0, as you state. When the distance is 0, two lines touch/intersect.