In: Advanced Math
Let A and B be two non empty bounded subsets of R:
1) Let A +B = { x+y/ x ∈ A and y ∈ B} show that sup(A+B)= sup A + sup B
2) For c ≥ 0, let cA= { cx /x ∈ A} show that sup cA = c sup A
hint:( show c supA is a U.B for cA and show if l < csupA then l is not U.B)