Respuesta :

(The sequence is neither arithmetic or geometric.)

Answer:

aₙ=  n²-6

Step-by-step explanation:

The sequence:

- 5, -2, 3, 10, 19, ...

The difference between terms:

3, 5, 7, 9

The next term would be: 19+11= 30

Let's work out the formula:

  • a₁= -5
  • a₂= a₁+3= a₁+4-1= a₁+2²-1
  • a₃= a₁+5= a₁+3+5= a₁+8= a₁+9-1= a₁+3²-1
  • a₄= a₁+7= a₁+8+7= a₁+15= a₁+16-1= a₁+4²-1
  • ...
  • so
  • we can put for nth term:

aₙ= a₁+n²-1= -5+ n²-1= n²-6

Let's test this formula for 5th and 6th terms:

  • a₅= 5²-6= 25-6= 19
  • a₆= 6² -6= 30

So the nth term is:

  • aₙ=  n²-6

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