Question

Question 25 If a, b, c and d are in G.P. show that (a^2 + b^2 + c^2)(b^2 + c^2 + d^2) = (ab + bc + cd)^2 .

Class X1 - Maths -Sequences and Series Page 193

Answer 1

see attachment.
we can prove this type of questions easily with help of properties of it.