2,660 reputation
1614
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location Houston, TX
age 31
visits member for 3 years, 10 months
seen yesterday

Jul
8
comment Calculate $\sum_{k=1}^n \frac 1 {(k+1)(k+2)}$
@Elimination beat you to it by 22 seconds.
Jul
4
comment How to distinguish walking on a sphere or on a torus?
@dotancohen: Even if they could look up, people living on the outer parts of Planet Doughnut wouldn't have a view of the hole.
Apr
22
answered How many days are there in 70 years?
Apr
20
comment Kid's homework: 4 equations 5 unknowns? Going crazy!
@metacompactness: Not necessarily. For example, there could be half-siblings on this trip, with 1 father and 2 mothers. Or cases where one parent is unable to attend.
Apr
5
answered how to find the root in $x^3-x^2+6x+24$?
Apr
5
comment Derivatives of exponential functions
There's no $x$ in your function. Did you mean dt instead of dx?
Apr
5
answered Is $e^{-x}$ Lipschitz on the positive reals?
Apr
5
comment How can a piece of A4 paper be folded in exactly three equal parts?
It would be interesting to see an answer that relies on the $\sqrt{2}:1$ ratio of ISO paper sizes.
Mar
29
comment Why is there a different button for 'minus' and 'negative' on a calculator?
@Rahul: Based on your comment, I assume that you have an RPN calculator. However, I've also seen distinct - and buttons on infix-notation calculators like the TI-8x series, on which there's no obvious need to distinguish them.
Mar
29
comment Why is there a different button for 'minus' and 'negative' on a calculator?
This doesn't really answer the question. Although unary and binary minus are indeed distinct operations, a lot of programming languages, spreadsheet programs, etc., do manage to use the same symbol - for both of them.
Mar
29
awarded  Popular Question
Mar
29
comment Can a piece of A4 paper be folded so that it's thick enough to reach the moon?
Assuming a typical 0.1 mm thickness, how large would a sheet of paper need to be so that it could be folded 42 times?
Mar
28
comment Can a piece of A4 paper be folded so that it's thick enough to reach the moon?
1L << 42 is faster than calling a function ;-)
Mar
28
comment Can a piece of A4 paper be folded so that it's thick enough to reach the moon?
Just to verify, I measured a package of 500 sheets of paper, and it was about 5 cm thick. So, 0.1 mm per sheet is a good estimate.
Mar
28
comment Can a piece of A4 paper be folded so that it's thick enough to reach the moon?
A piece of A4 paper cut in half 42 consecutive times would be A46.
Mar
28
comment Why is the $O$ (zero) matrix important?
Do you understand why the number 0 is important?
Mar
28
answered Why do we limit the definition of a function?
Mar
21
awarded  Great Answer
Mar
21
awarded  Citizen Patrol
Mar
21
answered Is $\frac{0}{0}$ different from $\frac{1}{0}$?