Question

Arithmetic Progression

If the sum of the first n terms of an AP is 5n^2 + 3n, what is the first term
(that is S1)? What is the sum of first two terms? What is the second term?
Similarly, find the 3rd, the 10th and the nth terms.

please answer this question
And i will mark u as brainliest.
please show your answer in steps or mention properly!!!​

Answer 1

Answer:a=13

sum of first two term =36

2nd term=23

3rd term=33

10th term =103

nth term =10n+3

Step-by-step explanation:

sn=d/2 n^2+(a-d)n

5n^2+3n=d/2n^2+(a-d)n

from the equation

d/2=5

d=10

(a-d)=3

a-10=3

a=13

first term =13

sum of first two term

2nd term =a+d

                 =13+10

                   =23

sum of first two term =13+23

                                    =36

third term =a+2d

                 = 13+(2×10)

                  =13+20

                   =33

10th term=a+9d

               =13+(9×10)

                =13+90

                 =103

nth term=dn+(f-d)

              =10n+(13-10)

               =10n+3