Sequences and Series, Increasing/Decreasing

Increasing/Decreasing

f() (a real valued function) is monotonically increasing if, for every x1 < x2, f(x1) ≤ f(x2). f is strictly increasing if, for every x1 < x2, f(x1) < f(x2). Similarly, f can be monotonically or strictly decreasing.

The same definitions apply to sequences; just make sure x1 and x2 are integers. A series of positive terms produces a strictly increasing sequence of partial sums. A series of nonnegative terms produces a monotonically increasing sequence of partial sums.