C'mon... Just do it:var(y) = E(y^2) - E(y)^2 = E(x^4 + 4X^3 + 4x^2) - 1 = E(x^4) + 4E(x^2) -1 (E(x^3) =0 because pdf(x) is even) = 3 + 4 - 1 = 6

Not 100% sure I understand your question, but if you're looking to back out the the set of x,y coordinates corresponding to the points of a plot for which you have only a jpeg then you may want to look at the Google Chrome plugin named WebPlotDigitizer.

I thought about this a long time ago and wrote up my conclusions. Might help... http://arxiv.org/abs/0908.1444

it looks like y is supposed to be a wt, but you don't say that. the answer is obviously no if y outside of [0,1] is allowed. consider A = 2x2 identity, B = 2x2 with 0 diagonal terms, -3 off-diagonal. y = 4. then c = ((4,9),(9,4)) with det = 16-81...

Haven't tried this, and it's for windows-based tablets rather than iPads, but it's worth mentioning http://enventra.com/products/mobomath/overview.htm . It looks very cool... Anyone use this?

<t>We've got to define terms here in order to have a reasonable discussion... The skew between fixed strikes declines as expiration increases simply because the quantiles of the pdf that the strikes represent become closer together as expiration increases and the distribution spreads out. Only if th...

Yes, but will they also be on the website?

Dividends

Yes, but can you show it on the back of an envelope

<t>Otherwise known as the marriage problem... Here's the bank's optimal strategy if their goal is to maximize the likelihood of hiring the best candidate: When you're 1/e of the way through the sample you decide that the next candidate that's better than all the previous candidates is the one you're...

<r>What about <URL url="http://hardware.slashdot.org/article.pl?sid=06/03/23/1717259&from=rss"><LINK_TEXT text="http://hardware.slashdot.org/article.pl ... 9&from=rss">http://hardware.slashdot.org/article.pl?sid=06/03/23/1717259&from=rss</LINK_TEXT></URL>? Does anyone know if this result...

Never mind, I got it...

<r>How do you see Wilmott in RSS? I use Firefox and, normally, there's a little indicator next to the url that indicates whether there's an RSS feed that I can subscribe to by clicking on it (as per <URL url="http://www.mozilla.com/firefox/livebookmarks.html">http://www.mozilla.com/firefox/livebookm...

<t>Can anyone comment upon their rates? In particular: 1) What spread do you pay between the margin rate on money you borrow to pay for your longs and the short rebate rate you receive on the proceeds of short sales? 2) Also, do you lend out your longs, or are they held in a segregated account, or d...

<r>After a quick reading on <URL url="http://scienceworld.wolfram.com/physics/BuckinghamsPiTheorem.html"><LINK_TEXT text="http://scienceworld.wolfram.com/physics ... eorem.html">http://scienceworld.wolfram.com/physics/BuckinghamsPiTheorem.html</LINK_TEXT></URL>, I must admit that I don't see how the...