The recursion is:
T(n) = 5T(n/2) + O(n)
I solved for the time complexity using Master theorem and found Θ(n^2). but, the question has asked to find the upper bound in terms of Big Oh. Is there any principle to convert it into Big Oh form? I read some examples where they substituted some values and deduced but I couldn't understand.
Update: I apologize for writing the recursion equation wrong. The actual recursive equation for this question is:
T(n) = 2(n-1) + O(n)