Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Latest activity
Register
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
mathwonk's latest activity
M
mathwonk
replied to the thread
A
Question about existence of path-lifting property
.
or if you want to stick closer to the author's proof, basically you want to show that if 0 < t1 < 1, and the lift of gamma is defined on...
Saturday, 12:28 PM
M
mathwonk
replied to the thread
A
Question about existence of path-lifting property
.
here's a proof of the lebesgue number: define a function d(x) on C as "how far inside the cover" is the point x. I.e. d(x) is the...
Saturday, 10:59 AM
M
mathwonk
replied to the thread
A
Question about existence of path-lifting property
.
I like a little trick called a "lebesgue number", that he invented to clarify some of Riemann's integration concepts. If one has an...
Saturday, 10:40 AM
M
mathwonk
replied to the thread
Should I double up on math courses next school year?
.
you might enjoy tackling some of the class notes on my webpage, such as numbers 4,9, 10 (elementary algebra and geometry). The notes...
May 31, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
have you tried to answer this yourself? Let N be the null space of I-A, i.e. the null space of A-I. Then N is the subspace where A...
May 28, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
apologies again to the experts for these details, which are for my benefit. I want to understand geometrically what seems to be the key...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
Clearly, the vector notation is very powerful here, since matrix multiplication is linear, i.e. preserves vector addition. Thus if A is...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
without using normal subgroups, if M is any isometry, and p is any point, then the translation t taking M^-1(p) to p, makes the...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
this might be a reasonable intro to groups...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
cianfa72, For the orthogonal matrix and rigid motion stuff, you may see LADW sections 5.7 and 6.5.
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
since each element (presumably) has a unique such expression in RT, hence t' is also unique.
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
yes. if T is the subgroup of translations, then T is a normal subgroup, so if r is any rotation, the subgroup r^-1Tr is again equal to...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
you find a basis of the null space, then augment it by a basis of the orthocomplement (i.e. the column space), then in that basis the...
May 27, 2024
M
mathwonk
replied to the thread
I
3-parameter group of symmetries on the plane
.
cianfa72, you are right I made a brief misstatement about axis r, later stated correctly, I added a correction, thank you. As to I-A...
May 27, 2024
M
mathwonk
replied to the thread
B
Memorizing trigonometric identities
.
well if you know Post #5, you can solve for cos(x) = (1/2)(e^ix + e^-ix), and sin(x) = (1/2i)(e^ix - e^-ix), [I think], and then you can...
May 26, 2024
Forums
Back
Top