If a be the A.M. and x, y be the two G.M.'s between b and c, show that
       Â
The sum of first three terms of a G.P. is  and their product is -1. Find the terms.
The product of three numbers in G.P. is 125 and the sum of their products taken in pairs is  Find them.
The sum of three numbers in G.P. is 21 and the sum of their squares is 189. Find the numbers.
Let A be the first term and D be the common difference.
∴           Â
           Â
                                        ...(i)
                                        ...(ii)
                                         ...(iii)
Since  are in G.P.
∴             Â
Now, Â Â Â Â Â Â Â Â Â Â Â Â andÂ
      andÂ
      and Â
      andÂ
      andÂ
     Â
   p - q, q - r, r - s are in G.P.