Chapter 5

Arithmetic Progressions

Arithmetic Progression

Let us consider the following set of members :
1, 5, 9, 13, 17………….
9, 12, 15, 18, 21 ……..
-5, 0, 5, 10, 15………
1.3, 1.6, 1.9, 2.2 ……..…

All these sets follow certain rules.
In first set 5 - 1 = 9 - 5 = 13 - 9 = 17 - 13 = 4
In second set 12 - 9 = 15 - 12 = 18 - 15 = 21 - 18 = 3

.. and so on. In first set the number after 17 in 17 + 4 = 21 and in second set number after 21 is 21 + 3 = 24. In this way we find that in first set second number is 1+ 4 = 5, third number is 5 + 4 = 9 = 1 + 2 x 4 and son on.