JJMcJ (u/JJMcJ) - Readit News

JJMcJ commented on Datacenters in space aren't going to work taranis.ie/datacenters-in... · Posted by u/mindracer

To say the quiet part out loud, I don't think any serious companies have any intention to build a data center in space. There is no benefit in actually trying this. There is however, benefit in saying you'll do it to advance a narrative and distract from the problems terrestrial data centers are facing to an audience that mostly doesn't understand how heat transfer in a vacuum works.

JJMcJ · 17 days ago

Consider what it costs to lift material to orbit. How can it possibly make sense except as a science fair project?

JJMcJ commented on Calculus for Mathematicians, Computer Scientists, and Physicists [pdf] mathcs.holycross.edu/~ahw... · Posted by u/o4c

tzs · 24 days ago

Getting an old enough edition of Apostol's "Calculus" to not include linear algebra might be a bit challenging. Linear algebra was added to both volumes in their second editions, which came out in 1967 for volume 1 and 1969 for volume 2.

The second editions are still the current edition, so no worry that you might be missing out on something if you go with used copies. If you do want new copies (maybe you can't find used copies or they are in bad shape) take a look at international editions.

A new copy of the international edition for India from a seller in India on AbeBooks is around $15 per volume plus around $19 shipping to the US. Same contents as the US edition but paperback instead of hardback, smaller pages, and rougher paper. (International editions also often replace color with grayscale but that's not relevant in this case because Apostol does not use color)).

You can also find US sellers on AbeBooks that has imported an international edition. That will be around $34 but usually with free shipping.

JJMcJ · 20 days ago

I know where my confusion comes from.

I studied from a first edition of volume one before there was a volume two, so it wasn't marked as Vol I.

Friend dug it up from his old books, since I seemed to be quick learner.

JJMcJ commented on We stopped roadmap work for a week and fixed bugs lalitm.com/fixits-are-goo... · Posted by u/lalitmaganti

ChrisMarshallNY · 24 days ago

I love the idea, but this line:

> 1) no bug should take over 2 days

Is odd. It’s virtually impossible for me to estimate how long it will take to fix a bug, until the job is done.

That said, unless fixing a bug requires a significant refactor/rewrite, I can’t imagine spending more than a day on one.

Also, I tend to attack bugs by priority/severity, as opposed to difficulty.

Some of the most serious bugs are often quite easy to find.

Once I find the cause of a bug, the fix is usually just around the corner.

JJMcJ · 23 days ago

It's like remodeling. The drywall comes down. Do you just put up a new sheet or do you need to reframe one wall of the house?

JJMcJ commented on Calculus for Mathematicians, Computer Scientists, and Physicists [pdf] mathcs.holycross.edu/~ahw... · Posted by u/o4c

SanjayMehta · 24 days ago

Indian editions sometimes have different question sets to prevent students from using them in other countries' coursework.

They also have a hologram sticker alongside a printed warning that they are not for sale or export outside of India, Nepal and a couple of other countries.

JJMcJ · 24 days ago

I think those restrictions apply only to retail sellers in those countries, not to purchasers or used stores.

JJMcJ commented on Calculus for Mathematicians, Computer Scientists, and Physicists [pdf] mathcs.holycross.edu/~ahw... · Posted by u/o4c

tzs · 24 days ago

Getting an old enough edition of Apostol's "Calculus" to not include linear algebra might be a bit challenging. Linear algebra was added to both volumes in their second editions, which came out in 1967 for volume 1 and 1969 for volume 2.

The second editions are still the current edition, so no worry that you might be missing out on something if you go with used copies. If you do want new copies (maybe you can't find used copies or they are in bad shape) take a look at international editions.

A new copy of the international edition for India from a seller in India on AbeBooks is around $15 per volume plus around $19 shipping to the US. Same contents as the US edition but paperback instead of hardback, smaller pages, and rougher paper. (International editions also often replace color with grayscale but that's not relevant in this case because Apostol does not use color)).

You can also find US sellers on AbeBooks that has imported an international edition. That will be around $34 but usually with free shipping.

JJMcJ · 24 days ago

Thanks for the info on cheaper editions, not important to me but to others in USA it might be a big help.

JJMcJ commented on Calculus for Mathematicians, Computer Scientists, and Physicists [pdf] mathcs.holycross.edu/~ahw... · Posted by u/o4c

qntty · 24 days ago

Writing a calculus book that's more rigorous than typical books is hard because if you go too hard, people will say that you've written a real analysis book and the point of calculus is to introduce certain concepts without going full analysis. This book seems to have at least avoided the trap of trying to be too rigorous about the concept of convergence and spending more time on introducing vocabulary to talk about functions and talking about intersections with linear algebra.

JJMcJ · 24 days ago

Anyway you've already got Apostol - if it's just calculus as such get an older edition. Modern ones have extra goodies like linear algebra but have modern text book pricing (cries softly in $150/volume).

JJMcJ commented on It's hard to build an oscillator lcamtuf.substack.com/p/it... · Posted by u/chmaynard

JJMcJ · a month ago

Also if it oscillates does it oscillate at the frequency you want?

JJMcJ commented on The last-ever penny will be minted today in Philadelphia cnn.com/2025/11/12/busine... · Posted by u/andrewl

afavour · a month ago

> The United States is the only country that prints all denominations of currency in the same size. The US and Switzerland are the only two countries that use the same colors for all of their various bills. Needless to say, this sameness of size and color make it impossible for a blind person to locate the correct bills to make a purchase without some sort of assistance, or confirm that he or she has been given the correct change by the sales clerk. Even people with partial sight may have trouble distinguishing a $1 bill from a $10, especially if the bill is old and worn.

https://afb.org/blindness-and-low-vision/using-technology/ac...

JJMcJ · a month ago

The ten dollar bill has a somewhat different color than the other currency, somewhat yellowish.

JJMcJ commented on The last-ever penny will be minted today in Philadelphia cnn.com/2025/11/12/busine... · Posted by u/andrewl

Night_Thastus · a month ago

I'd say screw it, get rid of nickles and dimes as well. Quarters can stay, for now.

It's a complete waste of money and time continuing to mint such low-value currency. It can't be used for just about anything.

Unfortunately, I do see the problem with part of this. For a handful of items where it does matter, it will force people to use cards more if they want to avoid rounding. And the card providers already have a choke-hold on retailers, and the whole thing is basically a scheme that funnels money from the poor to the wealthy via interest and fees on the consumer, interchange fees, and rewards programs.

JJMcJ · a month ago

The last time a coin was dropped was the half penny in the late 1850s, when I think it was worth about 25 cents today, so there is a precedent for what you are suggesting.