Question

/ If the sum of the first n terms of an AP is
4n-nthen what is the first term (i.e. S.)?
What is the sum of first two terms? What is the
second term? Similarly, find the 3rd, 10th and
the nth terms.​

Answer 1

Answer:

Given, sum of the first n terms is 4n-n

i.e. Sn=4n-n

Step-by-step explanation:

Sn=4n-n

S1=4(1)-(1)

   =4-1

   =3

∴ S1=a1=a=3

S2=4(2)-(2)

   =8-2

   =6

∴ S2=6

  S2=a1+a2

a2=S2-a1

a2=6-3

a2 =3

we observed that,

a1=a2=3

then, d=0

∴ a3=3

 a10=3

also,

nth term is 3

an=3