If ∣z∣<1|z| < 1∣z∣<1, then 1+z+z2+dots1+z+z^2+\\dots1+z+z2+dots (infinite sum) converges to:
frac11+z\\frac{1}{1+z}frac11+z
0
infty\\inftyinfty
frac11−z\\frac{1}{1-z}frac11−z