Errors in college textbooks

[the game]

So working on my physics homework and this isn't the first time I've ran into this but for some of the example problems I've noticed that the books calculations are wrong. Would it make you nervous to find errors in your college textbooks?

[Ayla]

Ive found mistakes in textbooks for professional designations. It's only nerve racking when you don't know if you should write the right answer or the answer in the text.

[Garnier Fructis]

Errors in calculations aren't that bad. Errors in things like definitions or theorem statements are the really bad ones. Writing down the wrong definition for the Hamiltonian of a physical system would be very bad, for example.

Do you have an example, though? It's good to make sure that it's really an error and that you don't actually have a confusion.

[purebalance]

I was extremely irked today with typos on test. Granted it's semi off topic, but I mean this woman has a doctorate and yet constantly had -es words where it should have been -ed. So essentially on the same topic, both my case and the OP, at the very least it's unprofessional in that they couldn't take the time to proofread their words or their calculations.

[the game]

Errors in calculations aren't that bad. Errors in things like definitions or theorem statements are the really bad ones. Writing down the wrong definition for the Hamiltonian of a physical system would be very bad, for example.

Do you have an example, though? It's good to make sure that it's really an error and that you don't actually have a confusion.

by my calculations v = 113.1 cm. It's not a huge difference but it makes me wonder which answer I should be using.

[Saladbar]

It gives them an excuse, not that they need one, to retire that revision of the book and require students to buy a new revision for $150 instead of buying used copies.

[the game]

It gives them an excuse, not that they need one, to retire that revision of the book and require students to buy a new revision for $150 instead of buying used copies.

Jokes on them. I rent the ebook from amazon for like $60. Also I downloaded the instructors version for free.

[twiddler]

by my calculations v = 113.1 cm. It's not a huge difference but it makes me wonder which answer I should be using.

I wouldn't be surprised that their answer is actually right and accounts for sig figs.

[vhok]

by my calculations v = 113.1 cm. It's not a huge difference but it makes me wonder which answer I should be using.

i have seen errors in definitions in text books before, never calculations. this looks like a case of rounding down. in low level classes (assuming this is physics 100 something) it's simplified and they will round down to 110.. either way you're only using 2 significant figures so you would have used 1.1 either way.. ask your prof.

[endersblade]

i have seen errors in definitions in text books before, never calculations. this looks like a case of rounding down. in low level classes (assuming this is physics 100 something) it's simplified and they will round down to 110.. either way you're only using 2 significant figures so you would have used 1.1 either way.. ask your prof.

But that is still an issue. In real life applications, rounding down like that can be downright dangerous, if not costly.

[Theinquisition]

When I was pursuing my degree in electronics technology, I had a class called electro-mechanical devices and applications where the professor literally wrote the textbook. I spotted a error in a calculation and he gave me extra credit points worth 5% of my grade.

[the game]

When I was pursuing my degree in electronics technology, I had a class called electro-mechanical devices and applications where the professor literally wrote the textbook. I spotted a error in a calculation and he gave me extra credit points worth 5% of my grade.

I"m working on an electronics degree.

[Garnier Fructis]

by my calculations v = 113.1 cm. It's not a huge difference but it makes me wonder which answer I should be using.

It probably is a sig fig issue like the others said.

Significant figure rules are the bane of your existence if you aren't an experimentalist. I always hated this shit.

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But that is still an issue. In real life applications, rounding down like that can be downright dangerous, if not costly.

Significant figures aren't random rounding, though. It's pretty systematic. And annoying.

Rounding like this is really a reflection of the lack of precision in the data in. You can't get numbers out that are more precise than what you put into it, so if things in real life applications fail then it's mostly a problem of garbage in.

[the game]

It probably is a sig fig issue like the others said.

Significant figure rules are the bane of your existence if you aren't an experimentalist. I always hated this shit.

Honestly nobody has explained significant figures to me. After it was mentioned here I went and watched a youtube video on it.

[Garnier Fructis]

Honestly nobody has explained significant figures to me. After it was mentioned here I went and watched a youtube video on it.

I would, as someone suggested, ask your prof if he cares. If he doesn't care about sig figs than I'd not bother with it and just write numbers.

I've had like 2-3 classes where we cared about it, usually chem, and in the rest I just write however many digits 'feels right' and roll with it, and no grader has complained. Because they also don't care.

[AeneasBK]

Honestly nobody has explained significant figures to me. After it was mentioned here I went and watched a youtube video on it.

Please don't take this as a slight on your ignorance of significant figures, because it isn't intended that way it is just curiosity - that said, what level of maths had you studied to before starting your electronics degree?

[the game]

Please don't take this as a slight on your ignorance of significant figures, because it isn't intended that way it is just curiosity - that said, what level of maths had you studied to before starting your electronics degree?

when I got my associates in networking I went up to intermediate algebra. Since starting my bachelors in electronics I've gone up to College algebra and am currently in precalc and physics.

It's actually interesting that physics and precalc both required college algebra and apparently college algebra was supposed to touch on some trig. Which the class I took didn't. It's been rough because when I got to physics this semester we needed basic trig within the first couple of weeks. I had to get a crash course on basic trig from a girl that works in my office. She's in my physics class.

[the game]

Typically college algebra in the US doesn't go over any sort of trig. There's usually a separate trig course and you also usually do some trig in precal. I really didn't learn any trig until I took Calculus.



I've never had sig figs taught in any math course ever. It's always been physics or a chemistry course.

we're touching on some trig in precalc right now.

[AeneasBK]

It's interesting (to me anyway) just because I've always had this analogy for learning maths and to an extent physics and chemistry as being like towers, with the foundation being "learning to count" and then the lower levels are simple arithmetic and stuff and as you get strong at that you can build the next levels and so on and so forth all the a yup to towering spires, the only requirement is strong foundations and that each "level" is stronger than the one above (as opposed to subjects like "literature" where you can be incredibly specialised in one area and know nothing of another, which I view more as a petri dish, where ignorance is the centre and the edge is detailed understanding).

So I wonder what it must be like to sort of branch into high(er) level maths having possibly skipped what I previously would have considered "mandatory" levels of the 'tower' of knowledge.

Don't get me wrong, I know my anaolgy is kinda flawed anyway, I came up with it when I was about 10; it just took me by surprise that you would (and correct me if I'm wrong here) not really studied any trigonometry if you're doing a physics related course. And in case it bears repeating - none of this is meant to be a "omg how did you not know that" post (for all I can be a snooty dickhead on here )

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I've never had sig figs taught in any math course ever. It's always been physics or a chemistry course.

You are taught to leave answers with irrational numbers in them? I'd agree that is certainly better to do; sig. figs always came up in maths classes I was in as a result of calculating areas/volumes of circular shapes/objects... I think, it was all very long ago now

[Ahhdurr]

Looks like sigfigs like others have said.

As far as trig, memorize the unit circle and the relation between trig functions and you'll be fine.

Oh and the graphs of sine and cosine.

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I've always had this analogy for learning maths and to an extent physics and chemistry as being like towers, with the foundation being "learning to count" and then the lower levels are simple arithmetic

It's more like a pyramid.