Changing only the period changes the indexed edge times. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

With the longer period the third edge is later

For period 8 seconds, edge 3 is at 24 seconds.

38 s=24 s3\cdot 8\ \text{s}=24\ \text{s}
Longer periodThe same index lands farther right.period 8 sedges 4edge 3 at 24 slast 24 s

Shorter periods tighten every indexed edge time

The selected index stays the same while the period is reduced row by row.

Tntn8 s324 s4 s312 s2 s36 s\begin{array}{c|c|c}T&n&t_n\\8\ \text{s}&3&24\ \text{s}\\4\ \text{s}&3&12\ \text{s}\\2\ \text{s}&3&6\ \text{s}\\\end{array}

With the shorter period the same edge is earlier

Changing only the period to 4 seconds moves edge 3 to 12 seconds.

34 s=12 s3\cdot 4\ \text{s}=12\ \text{s}
Shorter periodSame count and index, smaller checked time.period 4 sedges 4edge 3 at 12 slast 12 s