a,b,c is three consecutive terms of an AP.
∴ Let a,b,c be a,a+d,a+2d respectively …(1)
x,y,z is three consecutive terms of a GP.
∴ Assume x,y,z as x,x.r,x.r2 respectively ...(2)
To Prove: xb−c,yc−a,za−b=1
Substituting (1) and (2) in L.H.S., we get
L.H.S. =xa+d−a−2d×(xr)a+2d−a×(xr2)a−a−d=(x)−d⋅(x)2d(xr2)−d=1x4×x2d⋅r2d×1xdr2d=1= R.H.S.
Hence proved.