Math Problem Statement

f(n)=93+4(n-1)Complete the recursive formula of [f(n)].

Solution

To complete the recursive formula for the function f(n)=93+4(n1)f(n) = 93 + 4(n - 1), we need to express it in a recursive form. A recursive formula expresses each term in a sequence as a function of the previous term(s).

The given function is: f(n)=93+4(n1)f(n) = 93 + 4(n - 1) This is an explicit formula, but we can convert it into a recursive form.

Step-by-step approach:

  1. Calculate the first term (Base case):

    • For f(1)f(1), plug n=1n = 1 into the formula: f(1)=93+4(11)=93+0=93f(1) = 93 + 4(1 - 1) = 93 + 0 = 93
    • So, the base case is f(1)=93f(1) = 93.
  2. Find a recurrence relation:

    • To express f(n)f(n) in terms of f(n1)f(n - 1), we need to subtract f(n1)f(n - 1) from f(n)f(n): f(n)f(n1)=(93+4(n1))(93+4(n2))f(n) - f(n - 1) = \left( 93 + 4(n - 1) \right) - \left( 93 + 4(n - 2) \right) Simplifying the equation: f(n)f(n1)=4(n1)4(n2)f(n) - f(n - 1) = 4(n - 1) - 4(n - 2) f(n)f(n1)=4n44n+8=4f(n) - f(n - 1) = 4n - 4 - 4n + 8 = 4 Therefore, the recurrence relation is: f(n)=f(n1)+4f(n) = f(n - 1) + 4
    • So, the recursive formula for f(n)f(n) is: f(1)=93andf(n)=f(n1)+4forn>1.f(1) = 93 \quad \text{and} \quad f(n) = f(n - 1) + 4 \quad \text{for} \quad n > 1.

Summary:

The recursive formula for f(n)f(n) is: f(1)=93f(1) = 93 f(n)=f(n1)+4forn>1.f(n) = f(n - 1) + 4 \quad \text{for} \quad n > 1.

Would you like any further explanation or assistance with another example?


Follow-up questions:

  1. How would the recursive formula change if the original equation was f(n)=93+4nf(n) = 93 + 4n?
  2. Can you identify the common difference in this sequence?
  3. What is the value of f(5)f(5) using the recursive formula?
  4. How would you prove that the recursive formula is equivalent to the explicit formula f(n)=93+4(n1)f(n) = 93 + 4(n - 1)?
  5. What would the recursive formula be for a sequence defined by f(n)=5n+2f(n) = 5n + 2?

Tip:

In general, to convert an explicit formula into a recursive formula, calculate the difference between successive terms and express it as a recurrence relation.

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Math Problem Analysis

Mathematical Concepts

Recursion
Sequences
Algebra
Arithmetic Sequences

Formulas

f(n) = 93 + 4(n - 1)
f(n) = f(n - 1) + 4

Theorems

Recursive Formula Conversion
Base Case and Recurrence Relation

Suitable Grade Level

Grades 7-9