Arithmetic ProgressionLet us consider a sequence a, a + d, a + 2d, a + 3d, ... where a is the first term of the sequence and d is the common difference.1) ![]() 2) nth term of this sequence is given by ![]() ![]() 3) Sum upto nth term of the sequence is given by ![]() ![]() 4) When three terms are in A.P., then the middle term is called as Arithmetic Mean of the other two. If a, b, c are in A.P. then ![]() Geometric ProgressionLet us consider a sequence a, ar, ar2, ar3, ...where a is the first term of the sequence and r is the common ratio. 1) ![]() 2) nth term of this sequence is given by ![]() ![]() 3) Sum upto nth term of the sequence is given by ![]() ![]() 4) Sum of an infinte Geometric Progression is given by ![]() ![]() 5) When three terms are in G.P., then the middle term is called as Geometric Mean of the other two. If a, b, c are in G.P. then b = √ac |