Question

If the 3rd and 9th term of an ap are 4 and -8 respectively then is there any term of this ap is zero

Answer 1

Answer:

5th term is 0

Step-by-step explanation:

3rd term = a + 2d = 4

9th term = a + 8d = -8

subtract

9th term - 3rd term

a + 8d - a - 2d = -8 - 4

6d = -12

d = -12/6 = -2

a + 2d = 4

a + 2(-2) = 4

a - 4 = 4

a = 4 + 4

a = 8

an = a + (n-1)d = 0

8 + (n-1) × -2 = 0

(n-1)× -2 = -8

n-1 = -8/-2

n - 1 = 4

n = 4 + 1

n = 5

therefore the 5th term is 0

verification

a + 4d

= 8 + 4(-2)

= 8 - 8

= 0

the series in AP

8, 6, 4, 2, 0 ..........

hope you get your answer

Answer 2

Answer:

Please refer the attachment dear