Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

Write an explicit formula that represents the sequence defined by the following recursive formula:

a_(1)=9" and "a_(n)=(1)/(3)a_(n-1)
Answer: 
a_(n)=

Write an explicit formula that represents the sequence defined by the following recursive formula:\newlinea1=9 and an=13an1 a_{1}=9 \text { and } a_{n}=\frac{1}{3} a_{n-1} \newlineAnswer: an= a_{n}=

Full solution

Q. Write an explicit formula that represents the sequence defined by the following recursive formula:\newlinea1=9 and an=13an1 a_{1}=9 \text { and } a_{n}=\frac{1}{3} a_{n-1} \newlineAnswer: an= a_{n}=
  1. Given Term and Formula: We are given the first term of the sequence, a1=9a_{1} = 9, and the recursive formula an=13an1a_{n} = \frac{1}{3}a_{n-1}. To find an explicit formula, we need to express ana_{n} in terms of nn without referencing previous terms.
  2. Identifying Pattern: Let's look at the first few terms to identify a pattern:\newlinea1=9a_{1} = 9\newlinea2=(13)a1=(13)×9=3a_{2} = (\frac{1}{3})a_{1} = (\frac{1}{3}) \times 9 = 3\newlinea3=(13)a2=(13)×3=1a_{3} = (\frac{1}{3})a_{2} = (\frac{1}{3}) \times 3 = 1\newlinea4=(13)a3=(13)×1=13a_{4} = (\frac{1}{3})a_{3} = (\frac{1}{3}) \times 1 = \frac{1}{3}\newlineWe can see that each term is (13)(\frac{1}{3}) times the previous term, which is characteristic of a geometric sequence.
  3. General Form of nth Term: The general form of the nth term for a geometric sequence is an=a1×rn1a_n = a_1 \times r^{n-1}, where a1a_1 is the first term and rr is the common ratio.\newlineIn our case, a1=9a_1 = 9 and r=13r = \frac{1}{3}.
  4. Substitute Values: Substitute the values of a1a_{1} and rr into the formula to get the explicit formula for the sequence:\newlinean=9×(13)n1a_{n} = 9 \times \left(\frac{1}{3}\right)^{n-1}\newlineThis is the explicit formula that represents the given recursive sequence.

More problems from Write variable expressions for arithmetic sequences