Question

show that a1,a2,.........,an,...... form an AP Where an is defined as below-an =3+4n and ii is an= 9-5n

Answer 1

Answer:

The given sequences are in A.P

Step-by-step explanation:

Formula used:

The n th term of A.P a, a+d, a+2d, ........ is

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

1.

$a_n=3+4n\\\\a_n=3+4n-4+4\\\\a_n=7+4n-4\\\\a_n=7+(n-1)4$

which is the n th term of A.P 7, 11, 15.......

2.

$a_n=9-5n\\\\a_n=9-5n-5+5\\\\a_n=4-5n+5\\\\a_n=4+(n-1)(-5)$

which is the n th term of A.P 4, -1, -6,......