Recent content by jimmypoopins

That's the book that I studied out of my first year as a graduate student in stat. I think should be easy to follow as a undergrad as long as you have the necessary background. The other book I have in my collection is Time Series Analysis and Its Applications: With R Examples (...

i think given that information, cov(xs,xt)=min(s,t)σ^2 only if var(xt)=tσ^2. i'd double check that the problem isn't a typo or something.

independent and stationary does NOT imply X is a poisson process. the opposite is true, but many stochastic processes that are independent and stationary are not necessarily poisson processes (brownian motion, for example has independent and stationary increments).

is var(xt)=σ^2 or σ^2*t? if it's σ^2*t, then you can say. cov(xt,xs)=cov(xt-xs+xs,xs) and use independent + stationary increments to prove it. i'm not sure if it holds true if it's simply σ^2 though...

actually i meant this: (\overline{f}\\(\textbf{a}))^{-1} \ast \overline{f}( \textbf{a}) \ast \textbf{b} = (\overline{f}\\(\textbf{a}))^{-1} \ast \textbf{a} \ast f(\textbf{b}) i'm not that great with latex, or i would have tried to explain it better; my apologies. i think...

it's been a really long time since i did anything math related, but i think if you * the inverse of everything to both sides (i.e. step 1, * (f^bar(a))^-1 to both sides, step 2 * b^1 to both sides, step 3 * a^1 to both sides, step 4 * (f(b))^-1 to both sides) you should end up with...

that looks about right, except for e) and g). also, on b, it it supposed to be xe^(2x)? on e), if you factor your answer you get Asin x + Bcos x + Csin x + Dcos x = sinx(A+C) + cosx(B+D). since A, B, C, D are just constants, you can tell that you don't really need the C or the D. on...

i haven't actually seen a problem like this come up, but i think similarly to finding the particular solution to something like lhs=t^2 is A+Bt+Ct^2, it'd be something like: Asin(x)+Bcos(x)+Ccos^2(x)+Dsin^2(x) i'm not 100% sure, but i'd try something like that and see if it works out...

it holds for any function. prove it for any function (you should be able to)

consider W_1+W_2. you'll get W_1+W_2 = \left(\begin{array}{c c} x+a & -x+b \\ y-a & z+c \end{array}\right) what would a basis for that be? and then its dimension? also, keep in mind the equation you posted, and think about what you said about \left(\begin{array}{c c} 0...

Course: MTH 411 Abstract Algebra II Description: Continuation of MTH 310. Permutation groups, groups of transformations, normal subgroups, homomorphism theorems, modules. Principal ideal rings, unique factorization domains, noncommutative rings, rings of fractions, ideals. Course: MTH 415...

I have room for one more class this semester, and I've narrowed it down to Abstract Algebra II or Applied Linear Algebra. I've taken a semester of abstract algebra and two semesters of linear algebra thus far. I'm interested in going to graduate school for either mathematical physics or...

awesome, thanks! i'll check them out

hello all. originally i was a physics major and took "modern physics" which briefly covered nuclear, particle, and quantum physics. i switched majors to math, and now I'm thinking of dual majoring in physics and mathematics, but i'd like to read a little bit about quantum physics before i go...

1. Suppose V = U \bigoplus W where U and W are nonzero subspaces of V. Find all eigenvalues and eigenvectors of P_{U,W}. As long as \lambda=0 is an eigenvalue of P_{U,W}, i can prove that \lambda=0 and \lambda=1 are the only eigenvalues and then find the corresponding eigenvectors. can anyone...