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location Houston, TX
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Dec
16
answered Prove the lecturer is a liar…
Dec
13
comment Travelling to the point of origin without using the same road twice
Note that's it's not true if there are only $n-1$ roads. (For example, consider 5 cities connected with 4 roads in an X-shaped graph.) What is it about adding the nth road that forces there to be a cycle?
Dec
12
answered Why does Trapezoidal Rule have potential error greater than Midpoint?
Dec
9
answered Help with standard deviation and probability
Dec
8
comment financial help. Too many numbers equal only a few. which combinations?
en.wikipedia.org/wiki/Subset_sum_problem
Dec
7
awarded  Custodian
Dec
7
reviewed Approve suggested edit on Area of a square in polar coordinates?
Dec
7
answered Area of a square in polar coordinates?
Dec
7
answered Which is the impossible voting in election?
Dec
3
answered How to prove that either $2^{500} + 15$ or $2^{500} + 16$ isn't a perfect square?
Dec
2
comment Proof that every circle has the ratio of $\pi$
@Omnomnomnom: A circle is the set of all points in a plane that are a given distance (called the radius) away from a given point (the center).
Nov
30
answered Finding the derivative of $2^{x}$ from first terms?
Nov
25
answered Is there a function that gives the same result for a number and its reciprocal?
Nov
16
comment how many types of calendars should he prepare
@ErickWong: All possibilities do occur a minimum of 13 times per 400-year cycle.
Nov
12
comment Prove $\log_5{30}<\log_8{81}$
Factoring out $5^{1995}$ from $30^{1995} < 5^{4216}$, that half of the inequality is equivalent to checking that $6^{1995} < 5^{2221}$.
Nov
8
comment About the raised negative sign in some basic textbooks
TI calculators also use this notation, with separate buttons for unary and binary minus.
Nov
8
comment What are some examples of notation that really improved mathematics?
Sexagesimal has the advantage of 60 being highly-composite, with 10 non-trivial divisors, compared to only 7 for 100 and only 2 for 10 itself. Fibonacci's notation is horrible, though. Something like 01;22:07:42:33:04:40 would give the same information with less clutter.
Oct
24
answered Why does the google calculator give tan 90 degrees = 1.6331779e+16?
Oct
24
comment Why does the google calculator give tan 90 degrees = 1.6331779e+16?
The reciprocal of cosine is secant, not tangent. Of course, for angles very close to $\frac{\pi}{2}$, the difference is negligible.
Oct
23
comment Prove: Dividing an odd number by 2 always produces a remainder of 1
How are you defining "odd number"?