Math Problem Statement

If a, start subscript, 1, end subscript, equals, 3a 1 ​ =3 and a, start subscript, n, end subscript, equals, left parenthesis, a, start subscript, n, minus, 1, end subscript, right parenthesis, squared, plus, na n ​ =(a n−1 ​ ) 2 +n then find the value of a, start subscript, 3, end subscripta 3 ​ .

Solution

To solve for a3a_3, we need to find the terms of the sequence using the given formula:

  1. We are given: a1=3a_1 = 3

  2. The recursive formula is: an=(an1)2+na_n = (a_{n-1})^2 + n

We need to find a3a_3.

Step 1: Find a2a_2

Using the formula for n=2n = 2:

a2=(a1)2+2a_2 = (a_1)^2 + 2

Substitute a1=3a_1 = 3:

a2=(3)2+2=9+2=11a_2 = (3)^2 + 2 = 9 + 2 = 11

Step 2: Find a3a_3

Now, using the formula for n=3n = 3:

a3=(a2)2+3a_3 = (a_2)^2 + 3

Substitute a2=11a_2 = 11:

a3=(11)2+3=121+3=124a_3 = (11)^2 + 3 = 121 + 3 = 124

Conclusion

The value of a3a_3 is: 124\boxed{124}

Would you like more details on the steps, or have any questions?

Related Questions:

  1. What is the general formula for finding ana_n in this sequence?
  2. How would the sequence change if the initial value a1a_1 was different?
  3. Can you find a4a_4 using the same recursive method?
  4. What are some common properties of sequences defined by recursive formulas?
  5. How does this sequence behave as nn becomes very large?

Tip: In recursive sequences, always start with the initial value and proceed step-by-step to find the next terms.

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Math Problem Analysis

Mathematical Concepts

Recursive Sequences
Algebra
Exponents

Formulas

aₙ = (aₙ₋₁)² + n

Theorems

Recursive Sequence Formula

Suitable Grade Level

Grades 9-11