JAMB - Mathematics (2002 - No. 22)
The sum to infinity of the series: 1 + (1/3) + (1/9) + (1/27) + ... is
11/3
10/3
5/2
3/2
คำอธิบาย
The series is geometric with common ratio \(\frac{1}{3}\).
\(S_{\infty} = \frac{a}{1 - r}\)
= \(\frac{1}{1 - \frac{1}{3}} \)
= \(\frac{1}{\frac{2}{3}}\)
= \(\frac{3}{2}\)