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I think this: http://en.wikipedia.org/wiki/Summation#Capital-sigma_notation http://en.wikipedia.org/wiki/Summation#Capital-sigma_notatio...
by indrax 16y ago
I think this:
http://en.wikipedia.org/wiki/Summation#Capital-sigma_notation http://en.wikipedia.org/wiki/Summation#Capital-sigma_notatio...
- ludwigvan 16y agoI agree, it probably comes from maths. As a side note, the first letters are used for constants, the last letters are for variables; and it was Descartes who popularized this usage: http://en.wikipedia.org/wiki/Polynomial#Notation http://en.wikipedia.org/wiki/Polynomial#Notation I believe they used i for index, and also for the reason that it wasn't used by other usages as above. Similarly, the integration sign is actually a long s, standing for sum. http://en.wikipedia.org/wiki/Integral_symbol http://en.wikipedia.org/wiki/Integral_symbol
- mechanical_fish 16y agoThis is correct. I assure you that the physics texts all tend to use i and j as index variables. Particularly for matrices, whose terms have a tendency to be written as M_i_j. [1] Remember that modern electronic computing was invented by mathematicians and physicists. --- [1] HN isn't about TeX, so read that as "M sub-i sub-j".