This lecture dices deeper into notions of asymptotic analysis such as the big-O notation, big-Omega notation, little-o notation, etc. We as well introduce recurrence equations as a tool to model the time-complexity of algorithms. We give example of recurrences and solve them based on the recursion tree. Merge sort is introduced with analysis using a recurrence equation and solving it showing that merge sort hits the lower bound of nlog for comparison-based sorting. Instruction language is Arabic, however, all presentation slides, concepts, equations, definitions, formalizations, etc., are given in English.