a1 = -1, an = \(\frac{an-1}{n}\), n ≥ 2
⇒ a2 = \(\frac{a1}{2}=\frac{-1}{2}\)
a3 = \(\frac{a2}{3}=\frac{-1}{6}\)
a4 = \(\frac{a3}{4}=\frac{-1}{24}\)
a5 = \(\frac{a4}{4}=\frac{-1}{120}\)
Hence, the first five terms of the sequence are -1 , \(\frac{-1}{2},\frac{-1}{6},\frac{-1}{24},and\frac{-1}{120}\).
The corresponding series is (-1) + \((\frac{-1}{2})+(\frac{-1}{6})+(\frac{-1}{24})+(\frac{-1}{120})\) + ....
Find the mean and variance for the following frequency distribution.
Classes | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
Frequencies | 5 | 8 | 15 | 16 | 6 |