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