Question

Solve the recurrence equations
T(n) = T(n - 1) +n
T(n) = 1

Answer 1

By using substituion we get following series:
n + (n - 1) + (n - 2)+ (n - 3)... 3 + 2 +1
Which is sum of 'n' natural members.
= $\frac{n(n+1)}{2}$ $\Rightarrow$ O($n^2$)