Question

hi guys please help me out​

Answer 1

hi I hope it helps you

Answer 2

Given series is in Arithmetic Progression.

1.3, 3.5, 5.7 ........ n

To find the sum of the series to the 'n' terms of the A.P.

Sum to the n terms of an A.P. is given as

S =

$\frac{n}{2} (2a + (n - 1)d)$

Where, S is the sum, n is the number of terms, a is the first term and d is the common difference.

Here, first term = a = 1.3

common difference = d = 3.5 - 1.3 = 2.2

So, we get S =

$\frac{n}{2} (2 \times 1.3 + (n - 1)2.2) \\ \\ = \frac{n}{2} (2.6 + 2.2n - 2.2) \\ \\ = \frac{n}{2} (2.2n + 0.4) \\ \\ = 1.1 {n}^{2} + 0.2n$

Hence, sum of A.P. to n terms = 1.1n² + 0.2n