If the pth,qth and rth terms of a G.P. are a, b and c respectively. Prove that aq−rbr−pcp−q=1.
Let A be the first term and R be the common ratio. Then,
a=pth term =AR(p−1)
b=qth term =AR(q−1)
c=rth term =AR(r−1)
Substituting values of a,b & c, we get,