# calculus textbook avoiding “nice” numbers: all numbers are decimals with 2 or 3 sig figs

Many years ago, my father had a large number of older used textbooks.

I seem to remember a calculus textbook with a somewhat unusual feature, and I am wondering if the description rings a bell with anyone here.

Basically, this was a calculus textbook that took the slightly unusual route of avoiding "nice" numbers in all examples. The reader was supposed to always have a calculator at their side, and evaluate everything as a decimal, and only use 2 or 3 significant figures.

So for instance, rather than asking for the $\int_1^{\sqrt3} \frac{1}{1+x^2}$, it might be from $x=1.2$ to $x=2.6$, say.

The author had done this as a deliberate choice, since most "real-life" math problems involve random-looking decimal numbers, and not very many significant digits.

Does this sound familiar to anybody? Any ideas what this textbook might have been?

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..why would you want this book? It would have you show results like $e^{3.14i} + 1 \approx 0$.... –  mathmath8128 Nov 21 '11 at 23:42

## 1 Answer

Though this is probably not the book you are thinking of, Calculus for the Practical Man by Thompson does this. It is, most famously, the book that Richard Feynman learned calculus from, and was part of a whole series of math books "for the practical man". The reason I do not think it is the particular book you are thinking of is that the most recent edition was published in 1946, so there would be no mention of a calculator.

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I don't see why the publication date of the book is a reason it isn't the right answer, since the exclusive use of 2 or 3 digit numbers in a calculus book is so strange there is probably just one such book! The idea that a calculator was needed for the book could simply reflect the experience of idmercer's father. Back in the 1950s or earlier readers would have had slide rules instead. –  KCd Nov 22 '11 at 1:06
@KCd That's very true, I was assuming the instruction to "have a calculator at their side" came from the book. –  process91 Nov 22 '11 at 1:30
The instruction to "have a calculator at your side" is not necessarily an exact quote from the book, and is just my vague memory of the intended approach. –  idmercer Nov 22 '11 at 3:10