If the [tex]\( n^{\text{th}} \)[/tex] term of an A.P. is given by [tex]\( a_n = 2n + 3 \)[/tex], then the common difference of the A.P. is:

A. 2
B. 3
C. 5
D. 1



Answer :

To determine the common difference of an arithmetic progression (A.P.) where the [tex]\(n^{\text{th}}\)[/tex] term is given by the formula [tex]\(a_n = 2n + 3\)[/tex], follow these steps:

1. Understand the general form for the [tex]\(n^{\text{th}}\)[/tex] term of an A.P.:
- The general form for the [tex]\(n^{\text{th}}\)[/tex] term of an arithmetic progression is typically written as [tex]\(a_n = a + (n-1)d\)[/tex], where [tex]\(a\)[/tex] is the first term and [tex]\(d\)[/tex] is the common difference.

2. Identify the given formula:
- The formula provided for the [tex]\(n^{\text{th}}\)[/tex] term of this specific A.P is [tex]\(a_n = 2n + 3\)[/tex].

3. Calculate the first term ([tex]\(a_1\)[/tex]) and the second term ([tex]\(a_2\)[/tex]):
- The first term ([tex]\(a_1\)[/tex]) is when [tex]\(n = 1\)[/tex]:
[tex]\[ a_1 = 2(1) + 3 = 2 + 3 = 5 \][/tex]
- The second term ([tex]\(a_2\)[/tex]) is when [tex]\(n = 2\)[/tex]:
[tex]\[ a_2 = 2(2) + 3 = 4 + 3 = 7 \][/tex]

4. Determine the common difference ([tex]\(d\)[/tex]):
- The common difference [tex]\(d\)[/tex] in an arithmetic progression is the difference between the successive terms. Therefore:
[tex]\[ d = a_2 - a_1 \][/tex]
- Substitute the values of [tex]\(a_2\)[/tex] and [tex]\(a_1\)[/tex]:
[tex]\[ d = 7 - 5 = 2 \][/tex]

Therefore, the common difference of the A.P. is [tex]\(\boxed{2}\)[/tex].