Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

f(n)=45*((4)/(5))^(n-1)
Complete the recursive formula of 
f(n).

{:[f(1)=◻],[f(n)=f(n-1).]:}

f(n)=45(45)n1 f(n)=45 \cdot\left(\frac{4}{5}\right)^{n-1} \newlineComplete the recursive formula of f(n) f(n) .\newlinef(1)=f(n)=f(n1) \begin{array}{l} f(1)=\square \\ f(n)=f(n-1) \cdot \square \end{array}

Full solution

Q. f(n)=45(45)n1 f(n)=45 \cdot\left(\frac{4}{5}\right)^{n-1} \newlineComplete the recursive formula of f(n) f(n) .\newlinef(1)=f(n)=f(n1) \begin{array}{l} f(1)=\square \\ f(n)=f(n-1) \cdot \square \end{array}
  1. Given Explicit Formula: We are given the explicit formula for the sequence:\newlinef(n)=45×(45)n1f(n) = 45 \times \left(\frac{4}{5}\right)^{n-1}\newlineTo find the recursive formula, we need to express f(n)f(n) in terms of f(n1)f(n-1).
  2. Find f(1)f(1): First, let's find f(1)f(1) by substituting n=1n = 1 into the explicit formula:\newlinef(1)=45×(45)11=45×(45)0=45×1=45f(1) = 45 \times \left(\frac{4}{5}\right)^{1-1} = 45 \times \left(\frac{4}{5}\right)^0 = 45 \times 1 = 45\newlineThis gives us the initial condition for the recursive formula.
  3. Express f(n)f(n) in terms of f(n1)f(n-1): Now, let's find f(n)f(n) in terms of f(n1)f(n-1). We know that:\newlinef(n)=45×(45)n1f(n) = 45 \times \left(\frac{4}{5}\right)^{n-1}\newlinef(n1)=45×(45)(n1)1=45×(45)n2f(n-1) = 45 \times \left(\frac{4}{5}\right)^{(n-1)-1} = 45 \times \left(\frac{4}{5}\right)^{n-2}
  4. Divide f(n)f(n) by f(n1)f(n-1): To express f(n)f(n) in terms of f(n1)f(n-1), we divide f(n)f(n) by f(n1)f(n-1):
    f(n)f(n1)=45×(45)n145×(45)n2\frac{f(n)}{f(n-1)} = \frac{45 \times (\frac{4}{5})^{n-1}}{45 \times (\frac{4}{5})^{n-2}}
    Simplifying the right side, we get:
    f(n)f(n1)=(45)\frac{f(n)}{f(n-1)} = (\frac{4}{5})
  5. Multiplying to get Recursive Formula: Multiplying both sides by f(n1)f(n-1), we get the recursive formula:\newlinef(n)=f(n1)×(45)f(n) = f(n-1) \times \left(\frac{4}{5}\right)

More problems from Write variable expressions for geometric sequences