Supremum and infimum

Find the Supremum (supS) and the infimum (infS) and indicate if supS is in the set S and if infS is in the set S:

S = {r in N: r^2 <= 15}
S = {r in Q: r^2 <= 15)}
S = {[(/1)^n][(n-1)/n]: n in N}
S = {x in R: x^2 + x - 1 < 0}

Solution Summary

This shows how to find supremum and infimum of sets.