160 reputation
7
bio website
location Germany
age 29
visits member for 2 years, 9 months
seen Oct 13 at 6:11


Sep
24
awarded  Autobiographer
Apr
10
answered Are mathematical articles on Wikipedia reliable?
Jan
14
comment Splitting a sandwich and not feeling deceived
@JohnU This is why a common version of this problem involves gold diggers or bandits, and a sack of gold powder.
Nov
9
comment How to put 9 pigs into 4 pens so that there are an odd number of pigs in each pen?
While I appreciate the clever tricky answers, wouldn't community wiki be the appropriate label for this question?
Oct
3
comment Literary statements that are false as mathematics
While a nice question, shouldn't it be Community Wiki?
Jul
28
accepted What form does a function take which desribes a linear coordinate system as seen through a perspective projection?
Jun
13
comment Why is $n$ divided by $n$ equal to $1$?
Wow, if I asked why is 1 + 1 equal to two, would it also become a question featured as the very first in the hot questions? I thought this was an experts site.
Jun
13
awarded  Critic
May
15
comment Advocating base 12 number system
Actually, the base 12 number system seems to have been common in the past, exactly due to 12 having many divisors. We even have traces of it in many languages (eleven and twelve, not oneteen and twoteen)
Mar
14
comment On prime numbers
If such a formula existed (which generates a bigger prime from any known prime), then we could generate arbitrarily large prime numbers, and there would be no sense in searching for even bigger and bigger primes.
Mar
14
comment On prime numbers
@JackM : there might be more than 48, we only know 48 of them. Actually, until a few weeks ago, we only knew 47.
Mar
8
comment What was the first bit of mathematics that made you realize that math is beautiful? (For children's book)
This is not a proof, this is THE proof of the Pythagorean Theorem. If you traveled back in time, and told Pythagoras himself that $a^2 + b^2 = c^2$, he either wouldn't understand you, or (after you defined what the square root means) wouldn't believe you.
Feb
21
comment What's next in this number series?
For such questions I always have the urge to answer π/2 and write up a function which generates exactly those first five elements. You can construct such a function easily with the use of the Dirac impulse. This proves the stupidity of such questions, which are not about any logical thinking, but about guessing what the examiner though about. Just like if they said "I though of a number, now guess which one is it.".
Jan
28
comment Funny thing. Multiplying both the sides by 0?
With the same trick, you could also prove that 1 = 2 because 1 × 0 = 2 × 0. This might make you understand better why it's wrong.
Dec
16
comment Why don't we define “imaginary” numbers for every “impossibility”?
We have, for example, x=1/0 if we extend the real numbers by adding infinity, and we specify 0 as -0 or +0 depending from which direction we take the limit.
Dec
1
asked What form does a function take which desribes a linear coordinate system as seen through a perspective projection?
Dec
1
comment Is there a simple way to turn a coordinate system “inside out”?
Actually, I should forget the parabola. As $a$ and $d$ are nearly identical (based on empiric data), it seems the function is nearly linear near the origin. I wonder what can it be...
Nov
30
comment Is there a simple way to turn a coordinate system “inside out”?
Maybe I'm too tired and don't see what the problem is, but your solution gives a convex parabola instead of the rotated one. You write $x=py^2+qx$ but use it as $x=py^2+qy$
Nov
30
comment Is there a simple way to turn a coordinate system “inside out”?
If the origin was moved to $(a,d)$ then $g(b) = e$, not $d$
Nov
30
comment Is there a simple way to turn a coordinate system “inside out”?
by the way, shouldn't it be $b=pe^2+qe$ ?