Question

How do you find the sum of the first 10 terms of `0.7+1.9+3.1+4.3+5.5+...`?

Answer 1

61

Explanation:

The sequence is an arithmetic progression with first term (`a_1`) 0.7 and common difference (`d`) = 1.2

The sum of the first `n` terms of an arithmetic progression is given by:

`S_n = n/2(2a_1+(n-1)d)`

`:. S_10 = 10/2(2xx0.7 +(10-1)xx1.2)`

`= 5(1.4 + 10.8) = 5xx12.2 =61`