- What is sum of ( 2 n 2 ) terms of the series 2 2 2 2 ?
1 8. If the sum of cubes of n natural numbers is 441, find the value of n and find the
sum of those terms.
- If the sum of cubes of the first n natural numbers is 225 , find the value of n
and find the sum of square of those terms?
- Show that 13 23 33 .............. 103 ( 1 2 3 ..... 10 )^2.
- If 210
1 2 3
13 23 33 3
n
n
, what is the value of n?
- A iron-bar with length one metre is divided into ten-pieces such that the lengths
of the pieces form a geometric progression. If the largest pieces is ten times of
the smallest one, find the length in appoximate millimetre of the smallest piece.
- The first term of a geometric series is a, common ratio is r, the fourth term of the
series is –2 and the 9th term is 8 2.
(a) Express the above information by two equations.
(b) Find the 12th term of the series.
(c) Find the series and then determine th e sum of the first seven terms of the
series.
- The nth term of The a series is 2n – 4.
(a) Find the series.
(b) Find the 1 0 th term of the series and determine the sum of first 20 terms.
(c) Considering the first term of the obta ined series as 1st term and the common
difference as common ratio, construct a new series and find the sum of first 8
terms of the series by applying the formula.
