If x=∑n=0∞ an,y=∑n=0∞ bn,z=∑n=0∞ cn where a,b,c are in A.P and |a|<1,|b|<1,|c|<1, then x,y,z are in

x=11−a; y=11−b; z=11−cGiven a, b, c are in A.P.-a, -b, -c are in A.P.1-a, 1-b, 1-c are in A.P So, 11−a,11−b,11−c are in H.P x,y,z are in H.P