Math Problem Statement

f(1)=5 f(n)=1/2 x f(n-1) n > 2

Solution

The function f(n)f(n) is defined as follows:

  1. f(1)=5f(1) = 5
  2. For n>2n > 2, f(n)=12×f(n1)f(n) = \frac{1}{2} \times f(n-1)

This appears to be a recursive function, where each term is half of the previous term.

Let's compute the values for the first few terms to better understand the pattern:

  • f(1)=5f(1) = 5
  • f(2)=12×f(1)=12×5=2.5f(2) = \frac{1}{2} \times f(1) = \frac{1}{2} \times 5 = 2.5
  • f(3)=12×f(2)=12×2.5=1.25f(3) = \frac{1}{2} \times f(2) = \frac{1}{2} \times 2.5 = 1.25
  • f(4)=12×f(3)=12×1.25=0.625f(4) = \frac{1}{2} \times f(3) = \frac{1}{2} \times 1.25 = 0.625
  • And so on.

It looks like f(n)f(n) follows a geometric progression with the common ratio 12\frac{1}{2}, and the first term f(1)=5f(1) = 5.

Would you like me to calculate more terms or derive a closed-form formula for f(n)f(n)?


Here are some relative questions to expand on this topic:

  1. How do you find a closed-form expression for a recursive sequence?
  2. What is the general form of a geometric sequence, and how does it apply here?
  3. How would you modify this sequence if the common ratio was a different value?
  4. What happens to f(n)f(n) as nn \to \infty?
  5. How do recursive functions like this one compare to explicit functions in terms of ease of calculation?

Tip: Recursive functions are useful when breaking down problems into smaller, simpler sub-problems.

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Math Problem Analysis

Mathematical Concepts

Recursive Sequences
Geometric Progression

Formulas

f(n) = (1/2) * f(n-1) for n > 2
f(n) = 5 * (1/2)^(n-1)

Theorems

Geometric Sequence Formula

Suitable Grade Level

Grades 9-12