929 reputation
1819
bio website wolfram.com
location United States
age 37
visits member for 4 years, 1 month
seen 2 hours ago

The gravatar was made with Mathematica, and inspired by this.

The contents of my posts are my own opinion, and do not reflect the opinions of my employer.


Oct
9
awarded  Organizer
Oct
9
revised Function as parameter in Wolfram Mathematica
edited tags
Oct
8
awarded  Yearling
Oct
6
comment “Change of basis” from standard vector space to matrix Lie algebra, and its inverse
give me a little time, it is a lot to digest.
Oct
6
comment Predicate Logic
A similar problem exists in your second statement, since your talking about a politician no one trusts, it should be $\lnot T(y,x)$.
Oct
5
revised Help understanding cross-product
added align environment to bring eqns within bounding box
Oct
5
suggested suggested edit on Help understanding cross-product
Oct
1
answered “Change of basis” from standard vector space to matrix Lie algebra, and its inverse
Sep
29
comment Simple problem with pattern matching in Mathematica
I was not aware of RepeatedNull, +1.
Sep
29
comment Wave propagation with variable wave speed
@lio, you're using first derivatives of $u$ which is not a wave equation. Did you mean $u_{tt} + c(x,t) u_{xx} = 0\;$?
Sep
29
comment differentiation of Polynomials
I think you've misinterpreted the OPs equation, the $3 x$ only divides the second term.
Sep
28
comment Confused about implicit differentiation
@Jordan, $dy^{20}/dy = 20 y^{19}$.
Sep
27
comment What is the result of $\infty - 1$?
+1, for "Cat - 1."
Sep
27
awarded  Nice Answer
Sep
27
revised Pure maths vs applied
added additional thoughts.
Sep
26
revised Pure maths vs applied
added clarifying statement
Sep
26
comment Pure maths vs applied
If your interested in the use of Lie algebras in quantum, the book by Lipkin is a good read, and it's a Dover reprint! Essentially it shows you how to extract a lot of information from the Hamiltonian by just knowing the operator algebra.
Sep
25
comment Do real matrices always have real eigenvalues?
@commenter. No, the "iff" is absolutely correct. Please review the fundamental theorem of algebra and the definition of the characteristic polynomial.
Sep
25
comment Do real matrices always have real eigenvalues?
@commenter, no. The equation $A v = \lambda v$ has a non-trivial solution iff $\det(A - \lambda I) = 0$ which is identical to finding the roots of a polynomial in $\lambda$. We know the roots of a polynomial with real coefficients may have complex roots. If we try to restrict ourselves to only real roots, we're not guaranteed to find all of them.
Sep
25
awarded  Critic