Please read the question carefully. I have posted this 2 times now and I keep getting the same poor response that makes no sense. They answering with only big-O while this question clearly includes a theta as well. So, I ask that someone actually take the time to read and answer the question

Let f1 and f2 be asymptotically positive non-decreasing functions. Prove or disprove each of the following conjectures. To disprove give a counter example.

If f1(n) = O(g1(n)) and f2(n) = O(g2(n)) then f1(n)+ f2(n)= theta(g1(n) + g2(n))