## Calculus: Early Transcendentals (2nd Edition)

a) First four terms: $1,3,6,10$ b) Limit doesn't exist
$$\sum_{k=1}^{\infty} k$$ Part A) $a_1 = 1$ $a_2 = 1 + 2 = 3$ $a_3 = 3 + 3 = 6$ $a_4 = 6 + 4 = 10$ Part B) Limit doesn't exist because sum seems to be increasing without a limit as $k$ increases.