Question

if the nth term of an AP is (2n+1)
then the sum of its first three terms is
CBSE 2012
a)6n+3
(b)15
(c) 12
Id) 21​

Answer 1

Answer:

15

Step-by-step explanation:

An=2n+1

A1= 2(1)+1 =3

A2= 5

A3=7

Sum of first three terms-

A1+a2+a3= 15

THANK YOU

HOPE YOU UNDERSTAND IT

Answer 2

Answer:

15

Step-by-step explanation:

tn = 2n +1  

t1 = 2+1 =3

t2 = 4+1 = 5

t3 = 6 +1 = 7

S3 = 3 + 5 +7 = 15..