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Oct
26
answered Simplifying expressions when taking limit to infinity
Sep
18
revised why binary is read right to left
added 12 characters in body
Sep
18
revised why binary is read right to left
added 12 characters in body
Sep
18
answered why binary is read right to left
Aug
25
answered Does $G$ always have a subgroup isomorphic to $G/N$?
Aug
13
comment If $ P(A) = 0 $ is $ A $ a null event?
@user159813 The fact that the "event is a non empty set" does not make the event "non-null". The set of pairs of integers that sum to 13 is non-empty but it's impossible to roll 13 with two ordinary dice.
Aug
5
comment In calculus, which questions can the naive ask that the learned cannot answer?
First, you don't need table look-ups to compute elliptic integrals. There are a variety of methods for computing them. Second, in what sense can you not exactly calculate the arc-length of an ellipse but can exactly calculate the arc-length of a circle?
Aug
4
comment using the same symbol for dependent variable and function?
This is a problematic area. Despite functions playing a central role in much of mathematics there isn't a clear unambiguous notation that mathematicians agree on. I think a good modern view is that $y$ is a function and $y(t)$ is the value of the function evaluated at $t$ in which case it (usually) makes no sense to say $y=y(t)$. But others take the view that $y=y(t)$ is a special use of notation that emphasises that $y$ is a variable that depends on $t$ and so is perfectly acceptable.
Aug
4
revised Computing the sum of an infinite series
The sum is not the same as the series itself
Aug
4
suggested suggested edit on Computing the sum of an infinite series
Jul
29
answered Examples of “Non-Logical Theorems” Proven by Logic
Jul
24
comment Can universal instantiation be used more than once?
If technique X can only be used once in a proof, and I use it to prove A implies B, and use it to prove B implies C, then I wouldn't be able to combine these proofs to show A implies C as that would require two uses, and mathematics would pretty well come to a halt.
Jul
20
awarded  Yearling
Jul
14
comment Why is the height of a heap defined as $\lg n$?
See mathworld.wolfram.com/Lg.html for some discussion of what the notation $\mathop{lg}$ (as opposed to $\log$ or $\ln$) means.
Jul
14
comment Are the real numbers really uncountable?
I'm not sure what the issue is @frogeyedpeas . When a mathematician says "there exists an x such that..." they're not saying "there exists an x, with definition Y, such that...". If you want to, you can study numbers with this property but that has no bearing on the existence of the other numbers.
Jul
14
awarded  Nice Answer
Jul
14
answered Are the real numbers really uncountable?
Jul
9
comment How do I know if I have imaginary numbers when using Newton Raphson Method?
I guess you're wondering what happens if you're trying to solve an equation that contains complex values, or from a complex starting point. The answer is that it gets complicated. Seriously complicated: chiark.greenend.org.uk/~sgtatham/newton
Jul
7
comment Integral of the square of a function
The integral can easily be non-negative even if the integrand is sometimes not real. Consider a function $f$ that takes a small imaginary value for a small region and otherwise takes large real values. Overall the real parts will dominate the integral giving a non-negative result.
Jul
6
answered Is $\infty = \frac{1}{0}$?