Timestamp: https://imgur.com/a/1iSk3CL

Hello r/mechmarket, I am looking to sell a few keyboards and buy a few items. Please see the below tables for what I am selling and buying. Feel free to make me any offers, will to listen to reasonable offers for any of the items.

Selling:

Buying:

TimeStump

Hello mechmarket community, looking to sell a good hand full of my collection to pay some bills.

For Sale:

• KBD8X MK I | Grey Bottom, Red Top Small dent bottom right corner, USB port has been CNC’d to fit newer KBD8X Type C PCB, unbuilt, Will include another Built PCB with BOX Reds | $320 Shipped

SOLD:

• KBD75 v2 | Dark grey and Light Grey Case, Includes Brass weight and Aluminum weight and Brass Plate | Built with Zilents lubed with 203g0 |$280 Shipped SOLD
• KBDFans 5 Degree Acrylic | $100 Shipped SOLD AS BUNDLE
• 1up 60% HS PCB | No Stabs Included |$55 Shipped SOLD AS BUNDLE
• Brass 60% Plate | $50 Shipped SOLD
  • Will Bundle the 5 Degree case, Brass plate for $135 Shipped SOLD AS BUNDLE
• Rama Works M65-A x KeyClack Solarized Edition with Silver Brass PVD | Built with lubed Gat Red Inks lubed 203g0 keycaps not included| $490 Shipped (premium for the lubed switches, and stabs) SOLD [ I will miss you :'( ]
• TX75 v1 | Cerakoted White Bottom, black Ano top some small dents but not noticeable | Tealios lubed by the previous owner | Looking to get what I paid for: $475 Shipped SOLD
• Matrix 1.2 OG HS Unbuilt Kit | Teal with Burnt Orange Plate, PCB converted to HS using Mill Max comes with everything including internal dampener and stickers | Switches and Keycaps not included | $720 Shipped
• Wood 60% Case ONLY | $40 Shipped
• Red Acrylic Alice | $100 Shipped
• Aquaria 60% HS | Includes gat black inks | keycaps not included | $285 Shipped

All prices are firm and include only shipping to the CONUS.

Will provide a quote for international shipping depending on location.

Please comment PM before messaging me (will not respond to chat)

Thanks Friends and have a good day!

https://imgur.com/a/Qn0BOAK

Down sleeping bag with synthetic insulation on the bottom from Mountain Equipment. Weighs 45oz in its stuff sack. Used ~10 times, always stored uncompressed. Washed with down cleaner. Comes with stuff sack and mesh storage bag, both pictured. I sleep warm and have used it comfortably around 30 degrees wearing just my base layer. Its a great bag, the enclosure and draft collar are both super adjustable. I'm only selling because I upgraded to something a little warmer and lighter for shoulder season backpacking in the Sierras.

$100 plus shipping depending on where you live.

So I have a question set: 'Multiply both sides of the matrix equation P(A) = 0 by A^-1 . Hence find a simple expression for A^-1 involving A and A^2 . Use this to compute the inverse of the matrix A.'

P(A) was found to be x^3 - 2x^2 - x + 2 (Using x as lamda)

However, I am confused as, wouldn't multiplying both sides by A^-1 be pointless on the side that is 0? Also isn't, A^-1 and the inverse of A the same thing?

Thanks in advance for any help.

I came across this question while revising my QM. I'm reading Sakurai, but I can't find anything about the degrees of freedom for a density matrix, nor what it can be used for. Does anyone know?

So I am asked to reduce the matrices in the following equations to echelon form, determine their ranks and solve the equation if it exists. For example one of them is:

|1 2 3||x| |8|

|3 2 1||y| = |4|

|1 1 1||z| |3|

1. Is there any general procedure for reducing something to echelon form? It seems I have to keep retracing my steps when I try row elimination.
2. Also if it is an echelon form, surely the matrices would always have full rank?

I'm starting an MS program that I hope to tailor towards heavy DS. Certainly, I get to take multiple CS and statistics courses. I'd like some suggestions for classes that would be beneficial for the analyses that are currently used. I've read quite a bit that matrix algebra would be helpful (could someone explain about more how?), but what about classes specifically about algorithms, bayesian statistics, pure math? Thoughts?

Edit: I'm at University of Chicago and while my program isn't a pure MS CS, I have access to all of their classes granted I have the level to get in them. Interests: That's the thing. I'm still unclear about the differences between machine learning, data science, statistics, computer science, software engineering, and if data science is this umbrella term that covers all of these. I'd love some discussion of this and suggestions for classes for these topics.

If anyone is familiar with the work of Dr. Cleve Backster, the pioneer of the polygraph (lie detector machine), there are some very interesting experiments indicating that all of life is connected on some subtle fundamental level. A documentary was done on this phenomenon using plants and brine shrimp back in 1979 and it still hasn't entered the mainstream. I wanted to share this excerpt from the documentary that demonstrates one such experiment. It certainly would explain a lot of phenomenon being reported in this subreddit... Here's the video link:

https://www.youtube.com/watch?v=E-7s_uz2Rm0

What other affects would this cause a problem to within the world as well?

Edit: The worth of a degree previously earned by normal means.

Title says it all. I have a sizable sparse adjacency matrix representing an undirected graph and I want the diagonal degree matrix, mxn sized, where if m==n: DD(m,n) = numDegrees(m) else DD(m,n) = 0;

Is the only way to compute this to write my own script or is there a matlab library call that helps out?