11th mathematics exercise questions with answers, Mathematics

Sequences and Series – Exercise 9.3[11-20] – Class XI

11. Evaluate  The sum of first three terms of a G.P. is 39/10 and their product is 1. Find the common ratio and the terms. Solution: Let a/r, a, ar be the first three terms of the G.P. a/r + a + ar = 39/10 ----(1) (a/r)(a)(ar) = 1 -----(2) From (2), we obtain a3… Continue reading Sequences and Series – Exercise 9.3[11-20] – Class XI

11th mathematics exercise questions with answers, Mathematics

Sequences and Series – exercise 9.2 [1 – 10]- Class XI

Find the sum of odd integers from 1 to 2001 Solution The odd integers from 1 to 2001 are 1, 3, 5 … 1999,2001 This sequence from an A.P. Here first term is a = 1 Common difference d = 2 Then, a + (n – 1)d = 2001 1 + (n – 1)2 =… Continue reading Sequences and Series – exercise 9.2 [1 – 10]- Class XI