Math Problem Statement

Find the domain and range for f(x) = √(4 - 2x) + 5.

Solution

To find the domain and range of the function f(x)=42x+5f(x) = \sqrt{4 - 2x} + 5, we need to consider the conditions under which the expression inside the square root is non-negative (since the square root function is only defined for non-negative values) and the values that the function can attain.

1. Domain of f(x)f(x)

The expression inside the square root, 42x4 - 2x, must be non-negative:

42x04 - 2x \geq 0

Let's solve for xx:

42x4 \geq 2x

2x2 \geq x

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

x(,2]x \in (-\infty, 2]

2. Range of f(x)f(x)

To find the range, we need to analyze the possible values of f(x)f(x). The square root function 42x\sqrt{4 - 2x} takes values from 0 to 4=2\sqrt{4} = 2 as xx ranges from 2 to negative infinity. Therefore, we have:

42x[0,2]\sqrt{4 - 2x} \in [0, 2]

Adding 5 to the square root, we have:

f(x)=42x+5f(x) = \sqrt{4 - 2x} + 5

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

f(x)[5,7]f(x) \in [5, 7]

Conclusion

  • Domain: (,2](-\infty, 2]
  • Range: [5,7][5, 7]

Would you like more details on any part of this process or have any specific questions?

Related Questions:

  1. What happens to the domain if the square root function is changed to a cube root?
  2. How would the domain and range change if the function were f(x)=42x5f(x) = \sqrt{4 - 2x} - 5?
  3. How do we find the domain and range of a rational function?
  4. Can the range be determined graphically, and how would the graph of this function look?
  5. What if the function were f(x)=42x+5f(x) = 4 - 2x + 5 without a square root? What would its domain and range be?

Tip:

Always remember to check the domain restrictions first when dealing with square roots, logarithms, or rational functions!

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Math Problem Analysis

Mathematical Concepts

Domain
Range
Square Root Function

Formulas

Square root condition: The expression inside the square root must be non-negative (≥ 0).
Domain: Solve the inequality 4 - 2x ≥ 0.
Range: Analyze the values of the function f(x) = √(4 - 2x) + 5.

Theorems

The function f(x) = √(expression) is only defined for non-negative expressions.

Suitable Grade Level

Grades 9-12