•  Consider another recurrence:

= O(1)                        if n = 1

• In the above recurrence relation O(1) means a constant. So we can replace with some constant c₁.
• Similarly,O(n) means a function of order n. So we can replace with C₂n.Hence, the recurrence can be rewritten as

• Solution by Iterative method:

<= 2( 2T(n/4) + C₂n/2) + C₂n

<= T() + C₂n + C₂n

<= (2 T() + C₂) + C₂n + C₂n

<= T() + C₂ n i