Question

Calculate s26 for the arithmetic sequence in which a14=4.1 and the common difference is d=1.7

Answer 1

Answer:

The value of $s_{26}=84.5$

Step-by-step explanation:

We have given  $a_{14}=4.1$

d=1.7

We have to find $s_{26}$

So, $a_{14}=a+13d$ from the formula

$a_n=a+(n-1)d$

When n=14

$a_{14}=a+(14-1)(1.7)=a+13(1.7)$

$4.1=a+22.1$

$-18=a$

$a=-18$

Using the formula:

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

When n=26

$s_{26}=\frac{26}{2}[2(-18)+(26-1)(1.7)]$

On simplification we get:

$s_{26}=84.5$