Question

In an AP sn=3n+5.. Then d=?

Answer 1

Answer:

$d=-5$

Step-by-step explanation:

Calculating, sum of first term

$S_{1}=3(1)+5$

$S_{1}=8$

So, first term is also equal to sum of first term i.e., $a_{1}=8$.

Now, calculating, sum of two terms-

$S_{2}=3(2)+5$

$S_{2}=11$.

Now, for calculating second term, subtract $S_{1}$ from $S_{2}$ -

$a_{2}=11-8$

$a_{2}=3$.

Now, Finally common difference is diference between the second term and first term -

$d=a_{2}-a_{1}$

$d=3-8$

$d=-5$