Question

find the 19th term of A.P-11,15,19​

Answer 1

Given:

First term, a = 11

Common difference, d = 15 - 11 = 4

no. of term, n = 19

To Find:

The 19th term of the A.P.

Formula:

an = a + ( n - 1 )d

Explanation:

By putting the respected values, we get

an = 11 + ( 19 - 1 )4

or, an = 11 + (18)4

or, an = 83

Answer:

The 19th term of the A.P is 83.

Answer 2

Answer:

19th term = 457

Step-by-step explanation:

AP = -11,15,19

a = T₁ = -11

T₂= 15

⇒ d = T₂ -T₁

⇒ 15 -(-11)

⇒15 + 11 = 26

∴ d = 26

Now,

     we know,

Tₙ = a + (n-1)d

⇒ T₁₉ = -11 + (19-1)26

⇒ T₁₉ = -11 + 468

⇒ T₁₉ = 457