"j" is used as this is a book for electrical engineers, as "i" was a notation for an electrical current in this trade. I found this explanation in "Introduction to Laplace Transforms for Radio and Electronic Engineers" by W.D. Day, 1960.

@Dog-ct8hs

Ай бұрын

ok

@NoobleeGt

Ай бұрын

Indeed, that's the explanation. J is also used as the current density, but as noone uses it in practice, there's no fear for any ambiguity ;)

@niteman555

28 күн бұрын

Funnily enough, when you study maxwell's equations, you then use J as the current density vector field

They dont make Math Sorcerors like you anymore as well

Its quite interesting for me to see a en enthusiastic person like you reviewing books everday I am also basically having my room filled up with Quantum Physics, Mathematics, Calculus(University Level along with Interesting Proofs), Programming , mathematical loops etc.More importantly I have my modela of inventions in my room about 7 models of Physics(Mechanics Related)...(Also shared that with Michio Kaku and he hardly responses anybody and I'm one of them whom he have responded..)

@tanmaysingh689

Ай бұрын

I think you're also interested so I can share my inventions PDFs with you I have file piled and I'm only 14½ years/old...Indian 10th Standard Student kindly respond sir...I have been watching you since your initial phase

@TheMathSorcerer

Ай бұрын

awesome!

We use 'j' for the square root of negative one because current is represented by 'i', so basically to avoid confusion. BTW the physicists used 'i' for current so we inherited that usage. Also, if you're interested in electronics, particularly guitar amps that still use tubes, another good book (free on the internet archive though there may still be some copies around) is "essentials of radio by morris slurzberg and william osterheld" published in 1948. It doesn't use complex numbers, etc. as it's aimed at technicians instead of engineers (my father gave me his copy when I was in 5th grade).

The cover looks very easy to fix before it completely falls apart, the rest of the book is in better shape than I thought it will be and the bindings are good.

The Great Depression resulted in several US School Districts economizing on their services. Generally, cutbacks were made in Secondary School so that many people did without High School Diplomas. When World War II started, the demand need for Soldiers educated enough to take and interpret orders made catching up on educational shortcomings a priority. This resulted in the invention of GED ( General Educational Development ). You have just stumbled into the rich treasure trove of the History of US Military Education. I invite you to look at several training videos that the US Military released to the public, in particular Private Snafu Cartoons. I know you are a Math Prof, but as a Teacher with some interest in History, you would be interested in this sidetrack when you take your coffee breaks.

@TheMathSorcerer

Ай бұрын

Amazing comment thank you ! Yes I have a huge collection of war education manuals lol. Love this stuff ❤️

Absolutely brilliant. I love the fact that you can appreciate such history in maths

There's so many places to find some of these rare books, and I've managed to find several after they've already sold out on Amazon. I consider myself lucky, and I'm not giving up my sources!

@TheMathSorcerer

Ай бұрын

☺️

@jercommodore4411

20 күн бұрын

I find many as a free PDF. I tried posting them here, but KZread deletes the links.

Remember the correspondence courses we could order back in the day from hobbie magazines that would teach you math and electronic principles. Did quite a few of those. You would do the exercises and take the exam in the back of the work book and send it in for them to correct it and send you a little certification. It was more for a feeling of accomplishment, but we did learn quite a bit.

@TheMathSorcerer

Ай бұрын

That is really cool!!

Paul Nahin has a couple of interesting books along these lines--check out "The Mathematical Radio: Inside the Magic of AM, FM, and Single-Sideband" as well as "The Science of Radio: With MATLAB and Electronics Workbench Demonstrations". Nahin has a bunch of really unique books, in that they're not quite textbooks, but at the same time he doesn't shy away from diving into mathematical details. I think his intended audience consists of high school seniors and undergraduate students that have had some calculus and basic physics.

Look at the quality of the print and paper. Great!

Thank you for sharing

Nice for electrical engineers thanks

I would guess they use j because i is associated with amps (in electrical/electronics). Maybe? Perhaps?

@wesselsprouts

Ай бұрын

Correct

I get a deep feeling of satisfaction watching your videos 😂 scratches something inside of me

Hey Can you do a review on the books from the 1800s ? Would love to see that

@TheMathSorcerer

Ай бұрын

Oh what a great idea, thank you!

@ojas3464

Ай бұрын

He did! E.g., Higher Algebra by Hall and Knight, whose first edition was around 1892. Was reprinted several times, with a few revisions. It cost about 10 cents (present conversion) I could not afford it during my student days, borrowed from a library and became one of my earliest motivations. Their discussion of Ratio and Proportions inspired to see the vanishing of a second order Determinant, then relate them to the Symmetries of a Square in Modern Language. Several decades later, I made it a point to buy it when I could afford, before retiring and regaining the same level of poverty as student days, but a huge difference is no tests, exams, marks, grades, etc., free to assign myself as much homework as I enjoy! pdf can be found for this book.

Can you make video about Fourier transformation

This book is PERFECT for me, since i am ham radio operator :))

i have that book minus cover was issued to my mom a radio engineer in army in wwii .

@TheMathSorcerer

Ай бұрын

Wow that is amazing!!

You can purchase an image scanner, become pdf sorcerer and make your subscribers a little bit happy ))

They use J in electronic and electrical engineering because i represents current. From ohms law I = V/R. I like doing mathematics but i still make a lot of stupid mistakes when i use I. Hope that helps..its usually related to a bit of history..

Since you're a collector of books, have you ever sent one off to be conserved and/or restored?

Дуже цікаво.

Wow, so amazing

Notice how the book lists Army-Navy-Marines but no Air Force? That's because in WWII the Air Force was part of the Army. It was turned into a separate branch of service after the war.

@TheMathSorcerer

Ай бұрын

Oh wow how interesting!!

Is this book available in a digitil format?

Looks like that came over on the mayflower

@TheMathSorcerer

Ай бұрын

❤️

"Wow...What is this?!?! It is crazy to think that there was a war!!" . Sounds like something a child would say. Is US history not covered in Cuba? Instead of speaking Spanish, you may been speaking German today had things gone differently.

You should scam to preserve on the internet