Question

(a) Find the nth term of the sequence 5.2. - 1. - 4.-7....
(5) Find the 20th 25th and the terms of the A.P. given by 21. 16. 11.6, 1. - 4.-9....​

Answer 1

answer:-

a. first term=5

common difference=2-5=-3

for finding nth term we need last term

I conclude last term as -40

an=a+(n-1)d

-40=5+(n-1)-3

(n-1)-3=-45

n-1=-45/-3

n-1=15

n=15+1=16

b. first term =21

common difference=16-21=-5

25th term=a+24d

=21+24(-5)=21-120= -99

20th term=a+19d

=21+19(-5)=21-95=-74