- “the n-th root of x”
- “the a-th derivative of b”
and even more troublesome:
- “the ϑ-th something…” (thetath?)
Is there a rule for which ordinal indicator to use on a name, or symbolic variable?
I have seen “n-th” used in various places, but I cannot say the same for other variable names (x, y, ϑ…)
Is “-th” the preferred indicator for unknown quantities? Is it even acceptable to use one, or should the sentence be rephrased into “the something of order ϑ” whenever possible?
NB. This question was never about the typesetting choice of “n-th” vs. “nth,” or even nth, but about the use of an ordinal indicator on symbolic variables: short names that are used to represent unknown quantities.