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visits member for 2 years, 10 months
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Apr
2
comment Notation for near optimal solution
Welcome to Math.SE, thanks for your question. Hope you stay around and contribute to the site. I haven't seen a standard notation for such things.
Apr
2
comment Can a transcendental number be an infimum of a set of rationals?
@MPW thank you, dumb typo, sorry
Apr
2
comment Can a transcendental number be an infimum of a set of rationals?
@Lubin see the edit, you just need to negate it.
Apr
1
comment How to compute the nth power of a matrix
As is clear from the above argument, it works as long as P is invertible, it doesn't rely on P being orthogonal
Apr
1
comment How to compute the nth power of a matrix
@RyanMcGaha Ryan, see the last update to the answer, I posted my numbers, do we agree?
Apr
1
comment How to compute the nth power of a matrix
@RecklessReckoner Typo, sorry, $P = \pmatrix{1 & -1\\-1 &2}$ and $P^{-1}$ is correct.
Apr
1
comment linear differential equation problem
@jesse fixed type
Apr
1
comment How to compute the nth power of a matrix
@RyanMcGaha it sounds like the order is wrong, shouldn't you have $P = \pmatrix{1 & -1 \\1 & 2}$ with $P^{-1} = \pmatrix{2 & 1 \\1 & 1}$?
Apr
1
comment How to compute the nth power of a matrix
@RyanMcGaha what are you using for $D$ and $P$?
Apr
1
comment linear differential equation problem
What are your thoughts about how to approach this problem? Please write some form of an attempt to solve it, and we will be glad to comment and give more hints.
Mar
28
comment Analytical question on year calculation.
@Medex well, it grows to 25 in 6 and tasks each year to double. So to grow half the height must have taken one year because it was half the height and then doubled in one year to reach the full height, so half the height was at 6-1=5 years
Mar
27
comment First order ODE with $f'(x) = 810(10)^x$
@recursiverecursion I found out what $f(x)$ was first and then took the derivative.
Mar
27
comment First order ODE with $f'(x) = 810(10)^x$
@recursiverecursion please see the edit
Mar
27
comment Finding Power Series Representations
Clever - partial fractions to geometric series.
Mar
27
comment Analytical question on year calculation.
@Medex I do. I also found an easier way to solve it. The hint is, it doubles in value each year and you need to find how long it took to grow to half the height at 6 years.
Mar
27
comment Degeneracy number of a ring graph
@triomphe yes, i am now confused too. the definition on wiki does not restrict graph size. need to look more into it, i am sorry.
Mar
27
comment Degeneracy number of a ring graph
@triomphe your last formulation is wrong, degeneracy is $$\min\{\max \mathrm{deg}(s) | s \in S\}.$$ This way, tree is 1-degenerate and cycle is 2-degenerate and star is 1-degenerate also. I got confused myself also, sorry.
Mar
26
comment Mixed integration problem
very nice trick
Mar
26
comment How do I do Linearization at a point that lies on a curve?
@Cozen $a=1$, so when all is done you get a linear function of $x$, hence the name linearization.
Mar
26
comment Double integral of $e^{x^2+y^2}dydx$?
Do you know about polar coordinates? Do you know about the Normal distribution? In what context are you asking this question, for which class is this the homework for?