The sum of the first five terms of an arithmetic progression is 65/2.Also ,five times the 7th is the same as six times the second term . Find the first term and the common difference of the AP.

Respuesta :

The first term and the common difference of the Arithmetic Progression which the given sum of the first 5 terms are respectively; 6 and 1/4

What is the nth term of an arithmetic sequence?

We are told;

Sum of first 5 terms of the AP = 65/2

Formula for sum of n terms of an AP is;

S = ⁿ/₂(2a + (n - 1)d)

65/2 = ⁵/₂(2a + 4d)

⇒ 65 = 5(2a + 4d)

13 = 2a + 4d     ------(1)

Formula for the nth term of an AP is;

aₙ = a + (n - 1)d

five times the 7th term is the same as six times the second term.

7th term is; a₇ = a + 6d

second term is; a₂ = a + d

Thus;

5(a + 6d) = 6(a + d)

5a + 30d = 6a + 6d

a = 24d

Put 24d for a in eq 1 to get;

13 = 2(24d) + 4d  

13 = 52d

d = 13/52

d = ¹/₄

Thus; a = 24(¹/₄) = 6

Read more about Arithmetic Sequence at; https://brainly.com/question/6561461