The recurrence relation T(n) = T(n/2) + n is solved using the recursion tree method. The tree's levels sum to n(1 + 1/2 + 1/4 + ...), which is approximately 2n. Alternatively, the substitution method yields the same geometric series, resulting in a time complexity of O(n). This segment demonstrates a step-by-step solution to a recurrence relation using the recursion tree method. The presenter meticulously breaks down the problem, showing how to sum the time complexities at each level of the tree, ultimately arriving at a Big O notation of O(n) by simplifying a geometric series and showing that the sum converges to a constant value. The visual explanation using a circle analogy further clarifies the convergence of the series.