Several terms of a sequence StartSet a Subscript n EndSet Subscript n equals 1 Superscript infinity are given below. ​{1​, negative 5​, 25​, negative 125​, 625​, ​...} a. Find the next two terms of the sequence. b. Find a recurrence relation that generates the sequence​ (supply the initial value of the index and the first term of the​ sequence). c. Find an explicit formula for the general nth term of the sequence.

Respuesta :

Answer:

(a) -3125, 15625

(b)

[tex]a_n=-5a_{n-1}, \\n\geq 2 \\a_1=1[/tex]

(c)[tex]a_n=(-5)^{n-1}[/tex]

Step-by-step explanation:

The sequence [tex]a_n$ _{n=1}^\infty[/tex] is given as:

[tex]\{1,-5,25,-125,625,\cdots\}[/tex]

(a)The next two terms of the sequence are:

625 X -5 = - 3125

-3125 X -5 =15625

(b)Recurrence Relation

The recurrence relation that generates the sequence is:

[tex]a_n=-5a_{n-1}, \\n\geq 2 \\a_1=1[/tex]

(c)Explicit Formula

The sequence is an alternating geometric sequence where:

  • Common Ratio, r=-5
  • First Term, a=1

Therefore, an explicit formula for the sequence is:

[tex]a_n=1\times (-5)^{n-1}\\a_n=(-5)^{n-1}[/tex]