>>127 これで分かる?
sin(x)/x = 1 - (x^2/6) + O(x^4)
log(sin(x)/x) = -(x^2/6) + O(x^4)
(1/x^2)log(sin(x)/x) = -(1/6) + O(x^2)
(sin(x)/x)^(1/x^2) = e^(-1/6)(1+O(x^2))

lim[x→0](sin(x)/x)^(1/x^2) = e^(-1/6)