Am I the only one annoyed by the tendancy to avoid negatives in front of an equation?

Alternate Form of Law of Cosines (from my textbook)

I’d much rather have

But the first in particular seems to be absolutely unthinkable, because of the -a^2 up in front.

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Filed under: Education, Mathematics |

John, on March 16, 2009 at 1:07 pm said:I agree with your preference.

I think a programmer would be more likely to lay things out as you suggest because there’s a strong tradition in programming for vertically aligning repetitive terms, more so than in math.

Jason Dyer, on March 17, 2009 at 4:13 pm said:My original background is CS, so I understand how you feel.

I already had a rant over at Invisible Math about how mathematicians (unlike programmers) seem to give no thought to how they name their variables.

mbork, on March 26, 2009 at 2:35 pm said:Hey, the same goes for fractions; people prefer 2x^2+2x+1=0 to x^2+x+\frac{1}{2}=0, don’t you think? But what about a huge preference for \frac{\sqrt{2}}{2} and not \frac{1}{\sqrt{2}}?

And the last comment is unfair. Please, read Halmos’s “How to write mathematics”, which is really a great reading.

John, on March 26, 2009 at 2:45 pm said:mbork: I think the preference for rational denominators was motivated by manual computational effort. For example, once you’ve looked up sqrt(2) in a table, it’s easier to divide the result by 2 than to take its reciprocal. Of course that doesn’t matter anymore, and I think the rational denominator convention isn’t followed as strictly as it once was.

mbork, on March 26, 2009 at 2:56 pm said:That is *really* interesting. I never thought about it this way! I always assumed that the reason is aesthetic: this way, you really see with the naked eye, that all numbers of the form, say, a+b\sqrt{2}, where a and b are rational, form a field and not only a ring.

BTW: how to embed (La)TeX code in the comments?

Jason Dyer, on March 26, 2009 at 5:08 pm said:mbork, I have a post about how to put LaTeX into WordPress:

https://numberwarrior.wordpress.com/2008/01/23/math-equations-in-wordpress-part-1/

jd2718, on April 6, 2009 at 2:58 am said:This bothers me less, though I dislike the inconsistency:

Jonathan