
No bullshit guide to math and physics - ivan_ah
http://nobsgui.de/to/MATHandPHYSICS/
======
thesimon
It is probably a great idea, but looking at the sample it looks like just
another textbook that is hard and complex:

[http://cl.ly/image/150V0z3T2b0g](http://cl.ly/image/150V0z3T2b0g)

In contrast to that, I found
[https://openstaxcollege.org/books](https://openstaxcollege.org/books) a
really awesome resource for learning physics (on an easy level)

Edit: Cutting out all the "bullshit" seems to make it hard for a "busy adult"
to easily learn the concept, but it actually seems like a good resource to
improve your knowledge which you simply forgot.

~~~
Keyframe
From those freebies it does appear dense. Is the whole book like that or just
the condensed mini guides?

~~~
ivan_ah
Just the freebies. The book(s) are less dense, but still get to the point. See
[http://minireference.com/static/excerpts/noBSguide_v5_previe...](http://minireference.com/static/excerpts/noBSguide_v5_preview.pdf)
and
[http://cnd.mcgill.ca/~ivan/miniref/noBSguide2LA_preview.pdf](http://cnd.mcgill.ca/~ivan/miniref/noBSguide2LA_preview.pdf)
for the book previews.

~~~
Keyframe
Very nice! When do you expect LA book to be done?

~~~
ivan_ah
I'd say beginning of the summer.

Finishing the applications chapter has been a massive time sinkhole! I wanted
to make a survey of all the cool things you can do once you have the tools of
linear algebra under your belt, but it's proving to be too much (Chapter 8 is
getting almost as long as the rest of the book).

In the coming weeks I'll be going over the latest draft and I might do a
scope-cut, in order to get it done more quickly. In summary I'd say end-of-
April for "dev close" and then probably a month for the final editing with my
editor, so June 1st for official release.

------
mirashii
While, like most people here, anything that claims to disrupt the textbook
industry gets me excited on instinct, even a cursory glance shows some major
issues with this that leaves me questioning whether someone who hasn't taken
these classes could do well.

An example from the first chapter.

> By the way, before we continue our discussion, let it be noted: the equality
> symbol (=) means that all that is to the left of = is equal to all that is
> to the right of =. To keep this equality statement true, for every change
> you apply to the left side of the equation, you must apply the same change
> to the right side of the equation.

What is a change, and why do I have to do it to both sides? Is deleting all
the exponents on both sides a valid change as long as I do it to both sides?
What about dividing both sides by 0? This is a woefully inadequate explanation
of manipulating equations. Maybe that's the bullshit that's been taken out,
but I consider it fundamentals which often trip a person up later due to
missing knowledge, and where I most commonly hear the phrase "Well you never
told me I couldn't..." come out of a struggling student's mouth.

~~~
ivan_ah
You make a good point, thought you're reading the "ice breaker" section which
is meant to be very introductory.

A few sections later I define "change on both sides" more formally as
"applying a function".

~~~
mirashii
These sorts of fundamentals are glossed over or not mentioned throughout,
though. For instance, both in and after the section on integration, the fact
that \int (f+g) = \int f + \int g. No explanation or limitation is placed on
that information. If I can do that, can't I also write \int (f/g) = \int f /
\int g ? These are common tripping points for many.

~~~
blixt
I actually have this book but haven't read it yet. As someone who joined the
web startup world when I was 14 and never went back to school, I need to work
on my math skills. I believe strongly in building knowledge by layers (start
with a simple overview, work you way towards the core of the subject) rather
than going in for the detail right away.

Would you say this book does the former well and just doesn't cover the
details very well, or is the book somehow flawed?

~~~
mirashii
I think it's one thing to say "Where and how you can apply these we can
discuss in more detail later, but for now assume that you can do x, y, and z
only" and another to omit details altogether to later correct (if corrected at
all) or leave what's available to inference.

From my reading and skimming of the samples provided, I wouldn't call this
book a "simple overview" as I would call it something that's so concerned with
getting to what appears to be the result/goal of a class like high school
physics, but misses the real point. For instance, the purpose of a high school
class many might take to be to learn how to take derivatives and integrals and
apply them to a few common types of problems. After all, that's what you spend
your time building up to, and what final exams on the class cover, so that's
the point, right? But to the contrary, the skills and problem solving you get
from doing those things in more rigor, with the details fully fleshed out
instead of glossed over, and with motivation properly explained, is the real
purpose.

In short, what I think this book will do is teach to the test, where the test
is a template final exam from the type of course it purports to cover. But as
we are all well aware, exams are not always proxies for whether you learned
the whole of the material. Based on the depth of information provided, I'd say
if your goal was to pass that class for your GED and never touch the
information again and never try to apply it outside of the small template
given by the textbooks, maybe it's useful. If you want practical knowledge
that you can apply in a variety of situations and use to continue your
education past this point, you're going to be missing a lot of very important
details.

~~~
ivan_ah
Thanks for reviewing the book. It's interesting that you came away with
conclusion that I aim to teach-to-the-test, which is in fact diametrically
opposite to my intent.

My main purpose with this book is to communicate to students the power of
using mathematics to model the real world. For this reason I made a great
effort to show the connections between the tools of calculus and the different
modelling techniques in physics. E.g. I make sure this reasoning is
understood:

    
    
       (sum F)/m = a => integrate_t + v_0 => integrate_t + x_0 = x(t) 
    

by covering it in Chapter 2, Chapter 4, and again in Chapter 5.

True there are some sections that are written more in a you-need-to-know-this-
because-its-going-to-be-on-the-exam (e.g. integration techniques, and series
convergence tests), but that's just the nature of these topics.

------
Brakenshire
It looks like 'no bullshit' in the sense of a heavily compressed primer using
a lot of notation. I think that is very useful if you're in the right frame of
mind. i.e. if you're happy with notation, and you want to refresh, or pick up
something just directly from the undiluted concepts. Say, if you haven't
looked at linear algebra for 5 years but suddenly need to use it for
something, a text like this is going to be great. Or maybe as almost a
syllabus/framework for connecting together concepts while you're doing a
course.

But I'm not sure it justifies the level of branding/rhetoric on the webpage.
If you think mathematics is hard, an introduction to a linear algebra section
which starts like this isn't going to change your mind:

> Linear algebra is the math of vectors and matrices. Let n be a positive
> integer and let R denote the set of real numbers, then R^n is the set of all
> n-tuples of real numbers. A vector v E R^n is an n-tuple of real numbers.
> The notation “E” is read “element of S”...

~~~
ivan_ah
Lol... in a previous version of the tutorial, I was using informal language to
define vectors as "arrays of numbers," which attracted a lot of negative
comments on HN because it wasn't mathematically precise enough.

Note the LA book is "Tome II" in the series, and assumes you've read the "Tome
I" (no BS guide to math & phys), which means the reader would be equipped to
understand more formal math descriptions.

But yeah... try giving an explanation for what a vector is that is both: (1)
understandable and (2) mathematically precise.

~~~
Retra
"A vector is a composite quantity that has a magnitude and a direction. If
something has a direction component and/or a magnitude component, it can be
represented by a vector, and if something is a vector, we can ask for its
direction or its magnitude (or both.)"

~~~
ivan_ah
Cool. That works well, if a bit geometrical. I'm going to think about
rewording the intro in this way.

However, I'd still have to introduce the notion of "coordinate vector"
somehow, which begs for the word "tuple" or array, neither of which the right
choice.

~~~
Retra
What I've described is the concept of a vector. You will have to determine the
notation, and in setting the notation, and ordered list of basis vector
coefficients is most commonly called a tuple, which is a generalization of
ordered pair / triple / quadruple, etc.. (Though 'tuple' doesn't usually imply
ordered.)

The reason 'array' doesn't really work is that arrays are generally understood
to be homogeneous in type, while tuples are usually Cartesian products. So if
you are using a Cartesian coordinate system, tuple is the ideal term.

[http://en.wikipedia.org/wiki/Tuple#Type_theory](http://en.wikipedia.org/wiki/Tuple#Type_theory)

------
JTon
FYI at the very bottom of the link there is a free stuff section where you can
sample the work from the book.

~~~
ivan_ah
That's right. The 'sympy_tutorial.pdf' in corresponds to Appendix D in the
book, and the mechanics tutorial corresponds to Chapter 2.

BTW, here's a link to a PDF version of the book preview
[http://minireference.com/static/excerpts/noBSguide_v5_previe...](http://minireference.com/static/excerpts/noBSguide_v5_preview.pdf)
(137pp, 6MB) in case flipping through low resolution .jpgs isn't your thing ;)

------
jplahn
I'm definitely going to look into this. Even with working on a second degree
in Engineering Mechanics, I've found that I have forgotten a considerable
amount of information I learned earlier in my degree (likely replaced by the
overwhelming information in CS). I would love to brush back up on those areas,
if only to overcome my fears of mechanical inadequacy. Without constant
application, material as complex as mechanics can simply slip away, so having
a book like this that hits on the high notes would be fantastic.

~~~
ErikRogneby
Khan Academy works for adults too. it goes all the way up through multi-
variable calculus. I've been pretty impressed.

[https://www.khanacademy.org/math/multivariable-
calculus](https://www.khanacademy.org/math/multivariable-calculus)

------
ayushgta
Forks interested in this should also see
[http://betterexplained.com/ebook/math/](http://betterexplained.com/ebook/math/)

------
Keyframe
Years (eons?) ago I bought something similar. Two book guide through math
which I still find useful to this day:

this: [http://www.amazon.com/Mathematics-Physical-Sciences-
Robert-L...](http://www.amazon.com/Mathematics-Physical-Sciences-Robert-
Lambourne/dp/0471852074)

and this: [http://www.amazon.com/Further-Mathematics-Physical-
Sciences-...](http://www.amazon.com/Further-Mathematics-Physical-Sciences-
Michael/dp/0471867233)

------
bkcooper
The feeling I get from that page is:

You've heard the expression "let's get busy"? Well this is a textbook that
gets _biz-zay_. Consistently and thoroughly.

------
mzaccari
My mental muscle for math has definitely atrophied since graduating with an
engineering degree. I’ve been looking for a nice way to exercise it, and this
looks like something that can get me there.

For a more in-depth discussion of physics, I’ve found the Feynman Lectures
[1,2] to be quite enjoyable. It’s a long read (I’ve only finished the first
book) but it is very thorough.

[1]
[http://www.feynmanlectures.caltech.edu/](http://www.feynmanlectures.caltech.edu/)
[2] [http://www.amazon.com/Feynman-Lectures-Physics-boxed-
set/dp/...](http://www.amazon.com/Feynman-Lectures-Physics-boxed-
set/dp/0465023827/ref=sr_1_3?s=books&ie=UTF8&qid=1427731116&sr=1-3&keywords=feynman)

~~~
Fenume
This [0] book is to mathematics what Feynman Lectures are to physics
(debatable, but I think it's worth the read).

[0]
[http://www.amazon.com/dp/0486409163/](http://www.amazon.com/dp/0486409163/)
(Mathematics: Its Content, Methods and Meaning)

------
ErikRogneby
Part of me hoped it would be written in the style of "Why's poignant guide to
Ruby".

~~~
jordigh
I think that's part of the alleged "bullshit", pretty stories that distract
from the actual material.

Then again, similar methods like in Learn You A Haskell For Great Good seem to
work on me. I do wonder how much time I spend trying to understand the jokes
and references.

------
Garlef
"Linear algebra is the math of vectors and matrices." "The matrix-vector
product is used to define the notion of a linear transformation"

This is BS. * First: Linear Algebra actually is the math of linear
transformations. * Second: No sane mathematician would define linear
transformations in terms of matrices.

Vectors and matrices are only one way to model linear transformations; They
help beginners to imagine linear algebra; But often, refraining from using
coordinates delivers a much clearer picture.

Maybe this should be called the "No BS guide to passing your engineering math
tests".

~~~
interdrift
Could you recommend a book for me so I can get deeper understanding?I'm a
college student(software engineering). I love linear algebra,I passed it easly
in my first semester, and I've done my studying and problems on Khan
Academy.org .

~~~
Garlef
"Linear Algebra Done Right":
[http://linear.axler.net/](http://linear.axler.net/)

From a math perspective some definitions could be "cleaner" but as a
first/second round it gives a very good perspective on linear algebra.

Some of the good stuff:

* The general theme is "direct sum decomposition".

* Determinants are delayed as much as possible. (There are many good reasons to do this.)

* Eigenvalues are not computed using the characteristic polynomial but the other way around; This reflects the algorithmic side: For performance reasons a computer usually calculates the char.polynomial using the eigenvalues and not by using determinants.

------
cbsmith
I'd love to see a table of contents, as it'd make it much easier to judge the
breadth of the subject matter.

One concern I have is I didn't see much that looked like discrete/finite math.
That compounds the mistake made by too many math curriculums. In particular,
statistics and probabilities rule our world these days (and seem destined to
do so only more in the future), yet so many people never even get a basic
education in them.

~~~
ivan_ah
For TOC, see
[http://minireference.com/static/noBSguide_v5_TOC.pdf](http://minireference.com/static/noBSguide_v5_TOC.pdf)

Note: the aim of the book is to cover mechanics (Physics 101) and calculus (I
and II). There is a second tome in the works that will cover optics, waves,
E&M, and vector calculus.

~~~
cbsmith
Ah, so this is focused on Physics.

Can't look a gift horse in the mouth, but I'm not sure of the intended use
case for such a guide. Normally you need a pretty formal foundation in Physics
to get much value from it, which is why I hopped on the discrete math picture
(lots of people do programming without any need for a formal math education).

------
jkot
Hm, that guide has lot of bullshit. Who cares about 4 different forces? Just
invent unified theory and compress it into single formula :-)

------
JohnLen
Will give a try on this book. Seems interesting

------
FrankenPC
As an analog from the electronics field, look at the Forrest Mims notebook
series. That is a superb example of how to take something insanely complex and
converting it to no bullshit.

The example I saw on the website looks like just another dry math textbook.
I've seen high school math books with more color and engaging concepts than
this.

------
peter303
If you need to use a guide, then it is B.S. No shortcuts to taking classes,
doing practice problems, and tests. The main ting the modernworld offers is
some nifty animations to illustrate these equations. We didnt have such in my
day.

------
crimsonalucard
Everybody starts off writing a textbook thinking that it will disrupt the
industry.

------
esalman
Which textbook/guide actually bullshits math and physics, may I ask?

~~~
ivan_ah
I'd say the standard UGRAD-level physics and calculus textbooks (Serway,
Giancoli, Stewart) are full of BS. Do you really need to read 1000+ pages to
learn calculus?

Textbooks after first-year university are normally much better and
bullshitfree. Graduate textbooks are usually solid.

Also, there are many free textbooks out there that are essentially bullshit
free, e.g. Calculus Made Easy by Silvanus P. Thompson available at
[http://www.gutenberg.org/ebooks/33283](http://www.gutenberg.org/ebooks/33283)

~~~
giardini
ivan_ah says:

"... Textbooks after first-year university are normally much better and
bullshitfree. Graduate textbooks are usually solid."

Amen!

To that end I recommend

"Mathematics Of Physics And Modern Engineering - Second Edition by I. S.
Sokolnikoff and R. M. Redheffer

[http://www.amazon.com/Mathematics-Physics-Engineering-
Stephe...](http://www.amazon.com/Mathematics-Physics-Engineering-Stephen-
Sokolnikoff/dp/0070596255/ref=sr_1_2?s=books&ie=UTF8&qid=1427734261&sr=1-2&keywords=mathematics+of+physics+and+modern+engineering+by+sokolnikoff#customerReviews)

Each chapter is independent, the text has a thorough index and covers most
everything. Few errors, well-illustrated, nicely-sized and pleasant on the
eyes. Most easy to read math book ever.

------
devty
How is this the top post in HN right now?

~~~
ebbv
I'd suggest that if a book on maths and physics doesn't interest you, then it
is you, not the book, which isn't a great fit for HN.

~~~
Steuard
Sure, but why _this_ book? I mean, it seems like a nice review guide and all
(though probably too terse for someone trying to learn the material for the
first time), but what about it is catching peoples' attention?

If I post about Tom Moore's fantastic "Six Ideas that Shaped Physics" textbook
series
([http://www.physics.pomona.edu/sixideas/](http://www.physics.pomona.edu/sixideas/)),
which is based on a career's worth of experience and many of the best ideas
from the active field of Physics Education Research, is that also a front page
link? (I'm teaching my Modern Physics course out of two of those volumes this
semester, and the students seem to really like it.)

~~~
crimsonalucard
Just add "bullshit" to the title.

"Six no bullshit ideas that shaped physics" Boom! front page.

------
pitt1980
t

------
wehadfun
From the mechanics section: >To solve a mechanics problem is to obtain the
equation of motion x(t)

This is exactly the type of bullshit that confuses people. To a regular person
what the fuck is x(t)?

~~~
ebbv
This is not what he was referring to as bullshit. What he was calling bullshit
is putting flowery stories around problems. E.g., "A train is traveling from
Dusseldorf to Amsterdam..."

x(t) is not bullshit just because you don't understand it. It's a mathematical
function. x is the function, t is time. Meaning that you can give the function
the time you're interested in and the function can tell you the motion of the
object. I'd imagine the text goes on from there to explain how you obtain the
function based on the sentence you quote.

The website lists prerequisites to reading the book, perhaps you don't meet
them?

~~~
wehadfun
thanks for the personal attack.

From reading the website it seem like an HR person or fireman could read this
book and understand mechanics which is bullshit. Even your explanation would
confuse them "x is the function?", "What function does x serve?", "How the
fuck would I give an 'x' the time?"

~~~
Retra
Reading and Thinking is still requirements. That's not the "bullshit" the
author is trying to avoid.

