Arithmetical progression, nth term, sn of an a.P. And arithmetic means
Answers
Arithmetic Progression
An arithmetic progression is a sequence of numbers in which each term is derived from the preceding term by adding or subtracting a fixed number called the common difference "d"
For example, the sequence 9, 6, 3, 0,-3, .... is an arithmetic progression with -3 as the common difference. The progression -3, 0, 3, 6, 9 is an Arithmetic Progression (AP) with 3 as the common difference.
The general form of an Arithmetic Progression is a, a + d, a + 2d, a + 3d and so on. Thus nth term of an AP series is Tn = a + (n - 1) d, where Tn = nth term and a = first term. Here d = common difference = Tn - Tn-1.
Sum of first n terms of an AP: S =(n/2)[2a + (n- 1)d]
The sum of n terms is also equal to the formulawhere l is the last term.
Tn = Sn - Sn-1 , where Tn = nth term
When three quantities are in AP, the middle one is called as the arithmetic mean of the other two. If a, b and c are three terms in AP then b = (a+c)/2
hope it's helpful :-)))