# Didn't get an equation

1. Feb 22, 2012

### xeon123

In the class, the teacher tried to find some measure that I didn't get. He subtracted two times, and divided by one of them.

$\frac{| T2 - T1 | }{T1}$

He found the duration and decided to divide by one of T. What was the purpose to divide by T?

T2 is the end time
T1 is the start time

2. Feb 23, 2012

### Staff: Mentor

The expression gives you the number of time intervals of length T1 in the interval from T1 to T2 (or from T2 to T1, if T2 < T1).

For example, let T1 = 10, and T2 = 60, and assume both are in seconds.
Then |T2 - T1|/T1 = (60 - 10)/10 = 50/10 = 5

There are 5 intervals of length 10 sec. between 10 sec. and 60 sec.