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Mar
26
comment What is the cartesian equation of $r = 1 + r \sin(\theta)?$
Well, r^2 = x^2 + y^2 and tan(theta) = y/x, and go from there.
Mar
13
accepted Population average age decreases with births AND deaths (kind of)?
Mar
13
comment Population average age decreases with births AND deaths (kind of)?
Of course! As long as the age decrease I describe is slower than the flow of time, the average age still increases. I will approve this answer as soon as stack lets me.
Mar
13
asked Population average age decreases with births AND deaths (kind of)?
Feb
28
answered Deriving the Area of a Sector of an Ellipse
Feb
27
answered How to calculate ellipse sector area *from a focus*
Feb
23
comment Calculating a Point that lies on an Ellipse given an Angle
@Atraxia this may help: math.stackexchange.com/questions/493104/…
Feb
23
comment Ellipse in polar coordinates
You may also want to look at my answer to math.stackexchange.com/questions/493104/…
Feb
23
answered Evaluating $\int_a^b \frac12 r^2\ \mathrm d\theta$ to find the area of an ellipse
Feb
20
comment Explain $\iint \mathrm dx\mathrm dy = \iint r \mathrm d\alpha\mathrm dr$
Why not take the area of the entire triangle (r^2/2*dtheta) and integrate over theta? ;)
Feb
5
awarded  Popular Question
Feb
1
revised Why is this coin-flipping probability problem unsolved?
fixed probability
Feb
1
answered Why is this coin-flipping probability problem unsolved?
Feb
1
comment Why is this coin-flipping probability problem unsolved?
What if you know in advance the coin will come up heads p% of the time, even for p!=50? That's sort of the question I asked at: quant.stackexchange.com/questions/2172/… (and no answers there yet either)
Dec
18
awarded  Critic
Dec
10
comment Best fit circle to “planetary” elliptical orbit?
@hardmath I'd be interested in seeing a solution like that, but the idea of using a circle is to make the math easy. If the nonuniform motion were ugly enough, it would defeat the purpose. However, I'll upvote (but not approve) an answer like that, just to see what it looks like.
Dec
10
comment Best fit circle to “planetary” elliptical orbit?
@RahulNarain OK, I'm willing to do that (ie, accept an answer that minimizes d^2, not d). It seems traditional to minimize the distance squared, even though it's different from minimizing the distance itself.
Dec
10
awarded  Custodian
Dec
10
reviewed Approve suggested edit on Best fit circle to “planetary” elliptical orbit?
Dec
10
asked Best fit circle to “planetary” elliptical orbit?