Reputation
801
Top tag
Next privilege 1,000 Rep.
Create new tags
Badges
7 18
Newest
 Yearling
Impact
~25k people reached

Mar
16
comment Earth population growth rate is exponential or logarithmic?
"barrycenter" is my cool new nickname :)
Mar
16
comment another follow up question: modeling with exponential distributions
Hint: if I'm doing the math right, Naomi's total time simplifies to 3/(lam1+lam2)
Mar
15
comment Earth population growth rate is exponential or logarithmic?
"nobody is modelling [...] exponential, quadratic , cubic, linear". Literally a contradiction as @A.S. notes.
Mar
15
comment Earth population growth rate is exponential or logarithmic?
If you have n points, you can always find an n-1 degree polynomial that matches those points exactly. In theory, you could have 3 points that match an exponential function and a quadratic at the same time (the function only has to agree with your data at 3 points, not everywhere). My main question: are you looking for an exact match or an approximate match?
Mar
15
comment Applying a general function an infinite number of times
en.wikipedia.org/wiki/Iterated_function may or may not be helpful
Mar
15
comment Find Nth Term of Sum Of Digits
If OEIS doesn't have a closed form, I'm guessing you'll be hard pressed to find one.
Mar
15
comment CDF expected value when Y=X^2
As @AndréNicolas notes, the square root actually has two values, so $P\left(X\leq \sqrt{Y}\right)$ isn't strictly correct.
Mar
15
comment Earth population growth rate is exponential or logarithmic?
The "i am assuming 3" is throwing me off. If you have 100 data points, it's still possible they are close to being quadratic, even if they are not exactly so. Just to confirm, you're looking for "best match" not a perfect fit, correct?
Mar
11
comment Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
Answer corrected.
Mar
11
revised Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
corrected answer
Mar
11
comment Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
Ugh, you're right! I knew that flipping A and N at the last second was a bad idea... I'll fix this shortly.
Mar
11
revised Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
minor grammra
Mar
10
answered Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
Mar
8
comment Whether or not to use Markov's formula
As others have noted, Markov's inequality does not apply to P(something) = something, only P(something) > something, and, by extension P(something) < something. You really should be able to solve this wo Markov's inequality though.
Mar
8
comment Intersection of two ellipses
Show us at least some work first. Perhaps start with the equations for the two ellipses?
Mar
8
comment Line $mx + ny = 3$ is normal to the hyperbola $x^2 – y^2 = 1$
Remember that the line has to touch the hyperbola at some point as well.
Mar
8
comment Boolean x'.y+x.y' solution
Hint: (x and not Y) OR (NOT x AND y)
Mar
8
comment Finding an angle in a triangle, when the length of one side is unknown and the distances from each vertex to an arbitrary point is known
So you're looking for a single solution that works regardless of whether S is in the triangle, outside the triangle, or on one edge of the triangle?
Mar
5
comment Sum of a particular Series
If it helps, Mathematica can't find a closed form for this sum or the equivalent integral.
Mar
5
comment How to find probability of the best choose?
en.wikipedia.org/wiki/Secretary_problem but it was called the beauty contest problem when I first heard about it.