Recent content by HackaB
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What is Your IQ? Share Your Experience
87 percent of people who begin sentences with "Statistically..." are full of horse poo.- HackaB
- Post #41
- Forum: General Discussion
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How Do You Simultaneously Diagonalize Two Commuting Hermitian Operators?
I think finding the eigenvectors of the individual matrices H1 and H2, as you were doing before, is the right way to go. Here are some things to keep in mind. Recap of what I said in the edit of my last post: since H1 and H2 are hermitian operators on a 3-d vector space, they each have a set...- HackaB
- Post #7
- Forum: Introductory Physics Homework Help
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How Do You Simultaneously Diagonalize Two Commuting Hermitian Operators?
When you say common set of eigenvectors, do you mean all eigenvectors in common or just some (like one in common, for instance)? edit: blanik: hermitian matrices always have a set of orthogonal eigenvectors that span the vector space they operate on. So you should have 3 different...- HackaB
- Post #4
- Forum: Introductory Physics Homework Help
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Graduate Are There Unique Surfaces in R^4 but Not in R^3?
So there is more than one way to imbed a n-1 sphere in Euclidean n-space? I take it that Alexander's horned sphere is an example of such an embedding, since it provides a counterexample to the theorem. What is meant by "embedding". What structure does it preserve?- HackaB
- Post #21
- Forum: Differential Geometry
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Solve Classical Mechanics: Find Force, Stable & Turning Points
danai_pa: Did you get an answer to this problem? I don't believe you will need to solve any cubic equations. Do what robphy said...set up the equation E = (1/2)mv^2 + U(x), where v = dx/dt and solve for dt. Integrate from one turning point to the other. That's half a period. This...- HackaB
- Post #7
- Forum: Introductory Physics Homework Help
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Solve Classical Mechanics: Find Force, Stable & Turning Points
how would you get k from that? Seems like you need to know what x is... :smile: Is that what you mean by "use some math"?- HackaB
- Post #6
- Forum: Introductory Physics Homework Help
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Graduate Are There Unique Surfaces in R^4 but Not in R^3?
Is that the jordan curve theorem?- HackaB
- Post #17
- Forum: Differential Geometry
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Graduate Are There Unique Surfaces in R^4 but Not in R^3?
Don't worry. Your insights are much appreciated, even if most of them go way over my head.- HackaB
- Post #11
- Forum: Differential Geometry
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Undergrad Linear and Abstract Algebra textbooks
Yes it is. It sort of relieves the tension in the room. Although it is possible to overdo it, too. One of my linear algebra teachers (we had different teachers for different semesters) was not so awesome. He was determined to fill up the lecture period with worked numerical examples, but...- HackaB
- Post #43
- Forum: Linear and Abstract Algebra
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Two watches, one thrown in the air.
Wow! Where did that come from? I'm sorry I participated in your little experiment. I'll let you continue trying to prove that everyone else besides you is an idiot. Good luck. edit: Why are you so angry?- HackaB
- Post #23
- Forum: Introductory Physics Homework Help
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Undergrad Linear and Abstract Algebra textbooks
He didn't give it, but I attempted to come up with one myself. Here are the axioms for vectors u,v,w in a vector space V and numbers a,b in a field K: 1) u + v = v + u 2) (u+v)+w = u+(v+w) 3) There is a zero vector O s.t v + O = v for all v 4) for every v and every O, there is an...- HackaB
- Post #35
- Forum: Linear and Abstract Algebra
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Two watches, one thrown in the air.
CarlB: It does make very good sense that the frame of the thrown watch should be considered the inertial frame and the held watch be should be the accelerated frame. But I don't understand why you insist that acceleration does not affect proper time. Sure, it doesn't appear explicitly in...- HackaB
- Post #21
- Forum: Introductory Physics Homework Help
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Undergrad Linear and Abstract Algebra textbooks
Okay, I'll repeat my question from post #18 since I'm still curious. Does anyone else find it surprising that you can prove that vector addition is commutative using the other 7 axioms that Sharipov gives (they seem to be the standard ones)? Or is this old hat? It was news to me. edit...- HackaB
- Post #33
- Forum: Linear and Abstract Algebra
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Two watches, one thrown in the air.
If you are just testing us to see if we can solve the problems you thought up, won't you at least tell us the right answer after we've given it a try?- HackaB
- Post #14
- Forum: Introductory Physics Homework Help
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Two watches, one thrown in the air.
Cool. Is it still the thrown watch that has less time elapsed, though? Seems like I remember reading that the elapsed proper time is maximized in free fall, so I was wondering if in GR it was the thrown watch that read a later time. He asked for the difference in elapsed time on the two...- HackaB
- Post #11
- Forum: Introductory Physics Homework Help