I accept SlipEternals conclusion:

1) lim (1-sinx/x)/x

^{2} < 1/6

Yes, it was nice, and completeley in line with the requirements of the challenge, invalidating my questioning in the above posts.

I assumed the conclusion was based on the sandwich theorem, which was implied as the path in previous posts of the ref in OP, and I couldn't see that despite a popular misconception which I correct in the following:

sinx/x and the Squeeze Theorem
Basically, 1) is correct by the definition of a limit, not by the sandwhich theorem.

(I still think the appropriate proof is geometric, in keeping with the definition of sinx/x and sine)