<< A partridge in a pear tree?

I have to cry fowl. The puzzle was posted before Xgiving, so would not have a Xmas reference.

Incidentally, when I wrote

<<
Let v_n be the vector in R^(n-1) defined as (1/n, 2/n,...,(n-1)/n).
Let w_n be the vector in R^(n-1) with the same coordinates in reverse order.
Find the limit as n -> oo of the angle between v_n and w_n.
(Try this without using numerical approximation or summation-of-powers
formulae.)
>>

I didn't mean to suggest the puzzle is solvable by guesswork.

--Dan