Question

Q.2: Which term of the AP: 21, 18, 15, . . . is – 81? Also, is any term 0? Give reason for your answer.

Answer 1

Step-by-step explanation:

Lets assume t=0 is the nth term.

if it yields n=whole number

then we have a term(0) in the given AP.

$t = a + (n - 1)d$

here

t=0

a=21

d= -3

$0 = 21 + (n - 1) ( - 3) \\ - 21 =( n - 1)( - 3) \\ 7 = n - 1 \\ n = 8$

here n = 8 = whole no.

hence 0 is a term in the AP.