Sum to infinity ∑ = arn − 1 = \(\frac{a}{1}\) − r a = \(\frac{1}{4}\) r = \(\frac{1}{8}\) ÷ \(\frac{1}{4}\) r = \(\frac{1}{s}\) × \(\frac{4}{1}\) = \(\frac{1}{2}\) S = \(\frac{1 \div 4}{1}\) − \(\frac{1}{2}\) = \(\frac{1}{4}\) ÷ \(\frac{1}{2}\) = \(\frac{1}{4}\) × \(\frac{2}{1}\) = \(\frac{1}{2}\)