If `a=sumx^n`, `b=sumy^n`, `c=sum(xy)^n` where `|x|,|y|lt1` then

if a=sum x^(n),b=sum y^(n),c=sum(xy)^(n) where |x|,|y|<1 then

if a=sum x^(n),b=sum x^(n),c=sum(xy)^(n)

If a=sum_(n=0)^(oo)x^(n),b=sum_(n=0)^(oo)y^(n),c=sum_(n=0)^(oo)(xy)^(n) where |x|,|y|<1 then

If a=sum_(n=0)^(oo)x^(n),b=sum_(n=0)^(oo)y^(n),c=sum_(n=0)^(oo)(xy)^(n) where |x|,|y|<1 then

If x=sum_(n=0)^oo a^n, y=sum_(n=0)^oo b^n where |a|<1,|b|<1 then prove that sum_(n=0)^oo (ab)^n=(xy)/(x+y-1)

if x=sum a^(n),y=sum b^(n),z=sum c^(n) where a,b,c are in AP then x,y,z are in

If a = Sigma_(n=0)^(oo) x^(n), b = Sigma_(n=0)^(oo) y^(n), c = Sigma__(n=0)^(oo) (xy)^(n) " Where " |x|, |y| lt 1 , then -

If a = Sigma_(n=0)^(oo) x^(n), b = Sigma_(n=0)^(oo) y^(n), c = Sigma__(n=0)^(oo) (xy)^(n) " Where " |x|, |y| lt 1 , then -

If x=sum_(n=0)^oo a^n, y=sum_(n=0)^oo b^n, z=sum_(n=0)^oo c^n where a,b,c are in A.P and |a|<1, |b<1, |c|<1, then x,y,z are in

If a,b,c are proper fractiion are in H.P. and x sum_(n=1)^oo a^n, y=sum_(n=1)^oo b^n, z= sum_(n=1)^oo c^n then x,y,z are in (A) A.P. (B) G.P. (C) H.P. (D) none of these