Question

Question 17 If the 4th, 10th and 16th terms of a G.P. are x, y and z, respectively. Prove that x, y, z are in G.P.

Class X1 - Maths -Sequences and Series Page 192

Answer 1

see attachment,
you can easily prove with help of basic properties of GP.

Answer 2

let first term of GP be a and common ratio be r

than 4th term is ar^3

10 th term is ar^9

16 the term is ar^15

ar^3,ar^9,ar^15

are in gp with common ratio r^6

hence proved