If |x|<1 then Ltn→∞(1+x)1+x21+x41+x8…..1+x2n−1=
11−x
11+x
1
1+x
Ltn→∞1+x1+x2⋅⋅⋅⋅1+x2n−1=Ltn→∞11−x1−x1+x⋅⋅⋅⋅1+x2n−21+x2n−1=Ltn→∞11−x1−x4n−41+x2n−1=11−x1−01+0=11−x.