CHAPTER 5:-
ARITHMETIC PROGRESSIONS
Arithmetic progression or as it is commonly called A.P. is one of the 3 type of progressions namely Arithmetic Progressions, Geometric Progressions and Harmonic Progressions. It refers to a sequence where the difference between any two consecutive terms is the same called the common difference.
Starting with the basics, we will go up to NTSE level questions here.
So let's start!
1. Find the common difference(d) of the following A.Ps: (i) 21, 24, 27.... (ii) 19,17,15,13..... Ans. (i) d = 2nd term - 1st term d = 24 - 21 d = 3 (ii) d = 2nd term - 1st term d = 17 - 19 d = (-2)
2.Find the nth term of the following A.Ps : (i) n = 6 A.P. = 56, 36, 16........ (ii) n = 97 A.P. = 27, 31, 35....... Ans. (i) a = 56 d = (-20) n = 6 nth term = a + (n-1)d = 56 + (6-1)(-20) = 56 + (-100) = (-44) (ii) a = 27 d = 4 n=97 nth term = 27 + (96)4 = 27 + 384 = 411