Question

which term of the following series is first negative term 39,35,31,27,23​

Answer 1

Answer:

11th term

Step-by-step explanation:

Un = 39 - 4n +4 = 43 - 4n ≤ 0 ,  -4n ≤ - 43 , n ≥ 10.75

n = 11

Answer 2

Answer:

Step-by-step explanation:

The given series is 39,35,31, 27,23 ,....

on comparing with the standard form of A.P, we have a= 39;  d = -4

Let an be the term whose value is 0

an = a+(n-1)d

39 +(n-1)(-4) =0

39 -4n +4 =0 ⇒4n =43

⇒ n =43/4 ⇒ in this series we can not find any term whose value is zero.

now let us see a11 ( 11th term)

a12 = 39 + (11-1) (-4)

= 39 -40=  -1

∴ 11 th term will have first negative term and it is equal to -1