Question

if the nth term of an ap is 2n+1 then find the sum of the first three terms​

Answer 1

Answer:

A1 = 2(1)+1 ==> 2

A2 = 2(2)+1 ==> 5

SO, D = A2-A1 ===> 5-2 ==> 3

SUM OF FIRST THREE TERM ==> 3/2 [2(2) + (3-1)3 ]

===> 3/2 [4 + 6]

==> 3/2 * 10

==> 15

ANSWER = 15

OR

A1 = 2(1)+1 ==> 3

A2 = 2(2)+1 ==> 5

A3= 2(3)+1 ==> 7

SO, A1+A2+A3 ==> 3+5+7 ==> 15

Answer 2

Hi there here's your answer

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