Math Problem Statement

Find the range of f (x) = 1 + 2 cos(πx) + 1/2

Solution

We are given the function:

f(x)=1+2cos(πx)+12f(x) = 1 + 2 \cos(\pi x) + \frac{1}{2}

First, simplify the constant terms:

f(x)=1+12+2cos(πx)=32+2cos(πx)f(x) = 1 + \frac{1}{2} + 2 \cos(\pi x) = \frac{3}{2} + 2 \cos(\pi x)

Now, we analyze the term 2cos(πx)2 \cos(\pi x). The cosine function cos(πx)\cos(\pi x) always has a range between 1-1 and 11, i.e.,

1cos(πx)1-1 \leq \cos(\pi x) \leq 1

Multiply this inequality by 2:

22cos(πx)2-2 \leq 2 \cos(\pi x) \leq 2

Now, add 32\frac{3}{2} to the entire inequality:

322f(x)32+2\frac{3}{2} - 2 \leq f(x) \leq \frac{3}{2} + 2

Simplify both sides:

12f(x)72-\frac{1}{2} \leq f(x) \leq \frac{7}{2}

Thus, the range of f(x)f(x) is:

[12,72]\left[ -\frac{1}{2}, \frac{7}{2} \right]

Would you like further explanation or details on any of the steps?

Related questions:

  1. What is the period of cos(πx)\cos(\pi x)?
  2. How do the constants affect the range of trigonometric functions?
  3. What is the maximum and minimum value of f(x)f(x) for specific xx?
  4. How can we find the range of other transformed cosine functions?
  5. Can the range change if we add more terms involving trigonometric functions?

Tip: When transforming trigonometric functions, always start by determining the range of the core function before applying any shifts or scaling.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Function Range
Cosine Function

Formulas

f(x) = 1 + 2 cos(πx) + 1/2
Range of cos(θ): -1 ≤ cos(θ) ≤ 1

Theorems

Range of Cosine Function

Suitable Grade Level

Grades 10-12