I got: 1/6, 5/6, 13/6, and 17/6
Note that it can't be 7/6 or 11/6 because that would result in sin(\pi t) = -1/2. We want only sine values that will result in positive 1/2
nect time just ask me, via private message, to open the old post and you can answer there.
I have linked it to the original post.