That said, I don't know
many other $40 word processors that do trig functions
in their tables.
To me it is a mystery that Pages does not have it. Not only has Appleworks had it for more than twenty years, there are plenty of freeware applications that have it. And on each of our harddisks, the function is present over and over again: in bc, in java, in perl, in Grapher, in Calculator.
And Pages' formulas support a few dozen other functions already. It would probably have cost them nothing to add trigonometry.
If you have a word processor without any support for formulas at all, I can understand it. But supporting things like ISERROR but not sine is very strange.