Question

Write the sequence of the following explicit formula:

1. sn = (-4)n , 1 <_ n

2. t_n = 92 -5n, 1<_n <_5

Answer 1

1) Here $S_n=(-4)n$ , $n\geq1$

Therefore $S_1=(-4)$

$S_2=(-8)$

$S_3=(-12)$

.

.

$S_n=(-4)n$

$\therefore$ In explicit form

{ $(-4),(-8),(-12),.....,(-4)n$ }

2)Here $t_n=92-5n,1\leq n\leq5$

Therefore, $t_1=92-5.1=87$

$t_2=92-5.2=82$

$t_3=92-5.3=77$

$t_4=92-5.4=72$

$t_5=92-5.5=67$

$\therefore$ In explicit form {$87,82,77,72,67$ }