[tex] a_1=1\\
q=\dfrac{1}{2} [/tex]
[tex] |q|<1 [/tex] therefore, the sum of this infinite geometric series can be calculated using the formula [tex] S=\dfrac{a}{1-q} [/tex].
So, [tex] S=\dfrac{1}{1-\dfrac{1}{2}}=\dfrac{1}{\dfrac{1}{2}}=2 [/tex]
If 2 is the sum of this infinite series, then you'll never reach it.