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comment What are the best references?
Do you want results applicable to general sequences and series, or for specific ones? Anyway, these topics are typically covered in intro real analysis (see Spivak's Calculus or Rudin's Principles of Mathematical Analysis)
Jan
21
comment How do you find Cov(a - b*X + c*Y , X)
it's a pretty simple exercise in unwinding the definition of cov
Jan
19
comment Pricing a riskless asset in the Black & Scholes market
A riskless asset has no variance in price (it is deterministic) by definition, so you're simply solving the ODE $dS_t/S_t = r dt$ and you get the answer you expect.
Jan
11
comment Questions regarding Martingales
think of increasing sigma fields as accumulation of information -- you perform an experiment and measure outcomes at each timestep. E(X|Fk) is a conditional expectation. Are there examples from the Wikipedia article you don't understand? See also this question and answers as well as the linked ones.
Jan
3
comment Preparation for an Exam in Probabilities
For future reference, it's probably better to only ask one question per post (which is not to say that you should only post one question, feel free to post as many as you like!) to keep the site nicer and increase the likelihood that you'll get answers to both.
Dec
28
comment How to compute the expected value of the sum of two random variables?
yep, that part is fine! i removed my comments to avoid confusing people
Dec
23
revised Poisson Process RAID disk failure
not poisson; edited tags
Dec
22
comment Reference request: calculus of variations
For math? Physics? Have you taken undergraduate real analysis/ODEs/ ... ?
Dec
20
comment Why is it possible to find the birth year by subtracting one's age from 114?
Today I'm 25, so i was born in 1989, but if tomorrow's my birthday then i was born in 1988?
Dec
20
awarded  Constituent
Dec
19
comment Should I Put My Lifesavings into the Lottery?
If you are risk averse, I'm sure you wouldn't. Maybe you should rephrase your question (I think you really mean to ask about the expected value here).
Dec
11
comment Why do we focus so much in math on functions (as a subclass of relations)?
Maybe related: mathoverflow.net/questions/121031/…, math.stackexchange.com/questions/354779/…
Dec
11
comment Best metric to measure histogram quality
i'm speaking out of turn here, but why don't you calculate a squared error (or something) on the difference between a reference histogram (like the 1st) and the lower quality ones?
Dec
11
comment Best metric to measure histogram quality
if you don't get an answer here, maybe the signal processing or statistics stackexchange could help.
Dec
11
comment Don't see the point of the Fundamental Theorem of Calculus.
The definition of (one kind of) an integral is the limit of a riemann sum, how do I know a priori that the given limit is an antiderivative?
Dec
9
comment Soft question: A good book for introduction to Lie group book
what's your background? what book is required by your course?
Dec
8
awarded  Caucus
Dec
5
awarded  Popular Question
Nov
22
comment basic calculus/analysis question. why is $\frac {dy}{dx} dx = dy$?
Well, think about what $\int y'(x) \mathrm{d}x$ is equal to. It's really just formal a formal expression at the intro calc level though.
Nov
2
comment If $H$ is a subgroup of $G$ and $a, b \in G$, how is $aH=bH$?
if $Z_4$ and $Z_3$ are the cyclic group on 4 and 3 elements, $Z_3$ is not a subgroup of $Z_4$... $Z_4$ has no element of order 3.