Question

Within the set of whole numbers , one set of numbers satisfies the recursive formula an=(an-1)^2-an-1, when a4=870 what are the first two terms of the sequence?

Answer 1

Answer: 3 and 6 will be the first and second term of the given series respectively.

Explanation:  since it is given-  $a_n=(a_{n-1} )^2-a_{n-1}$ and $a_4=870$

so, by replacing n by 4, we will get- $a_4=a_3^2-a_3$⇒870= $a_3^2-a_3$⇒ $a_3^2-a_3-870=0$

after solving this equation we will get, $a_3= -29$ and 30.

If $a_3= -29$, but it is not a whole number.

Thus,$a_3=30$ will be the value of third term of the given series.

Again, by applying the given condition $a_n=(a_{n-1} )^2-a_{n-1}$, $a_2= 6$ or -5 (not possible), so, $a_2=6$ will be the second term.

Similarly, $a_1=3$ or -2 but  we will go to the whole number.

Thus, $a_1=3$ will be the first term.

Answer 2

Answer:

A

Step-by-step explanation: