That one line was the part that stood out to me the most as well, but:
If you zoom in sufficiently at x = 0, f(x) = sin(x) looks indistinguishable from f(x) = x, whereas g(x) = cos(x) looks indistinguishable from g(x) = 1.
(also, sin(x) is negative approaching 0 from the left and positive approaching 0 from the right)
If you zoom in sufficiently at x = 0, f(x) = sin(x) looks indistinguishable from f(x) = x, whereas g(x) = cos(x) looks indistinguishable from g(x) = 1.
(also, sin(x) is negative approaching 0 from the left and positive approaching 0 from the right)