Question

If n term of an AP is(2 n+1) what is the sum of its first 3 term

Answer 1

Answer:

15

Step-by-step explanation:

Putting 1 in the given eq

A1 = 2(1) + 1

= 3

Putting 2

A2=2(2) + 1

= 5

Putting 3

A3=2(3)+1

=7

S3 = A1+A2+A3

=3+5+7

=15

Answer 2

2nd term = 2x2+1=5
Sum of first 3 terms = 3xproduct of middle term
=3x5=15