Math Problem Statement

Find the domain and range of the function f(x) = (x + 4)^2 - 5. Explain how you know.

Solution

Let's solve the problem step by step.

Given Function:

f(x)=(x+4)25f(x) = (x + 4)^2 - 5

1. Domain (D):

The function f(x)=(x+4)25f(x) = (x + 4)^2 - 5 is a quadratic function. Since there are no restrictions (like division by zero or square roots of negative numbers), the domain of any quadratic function is all real numbers.

Domain: D:(,)D: (-\infty, \infty)

2. Range (R):

To find the range, we analyze the vertex form of the quadratic function. The function is written as: f(x)=(x+4)25f(x) = (x + 4)^2 - 5

This is a parabola that opens upwards (because the coefficient of the quadratic term is positive). The vertex occurs at x=4x = -4, and the minimum value of the function occurs at the vertex. Substituting x=4x = -4 into the function: f(4)=(4+4)25=05=5f(-4) = (-4 + 4)^2 - 5 = 0 - 5 = -5 Thus, the minimum value of f(x)f(x) is 5-5. Since the parabola opens upwards, the function's values will increase from 5-5 to infinity.

Range: R:[5,)R: [-5, \infty)


Would you like more details on this solution? Here are 5 related questions to expand your understanding:

  1. How do you convert a general quadratic function to vertex form?
  2. Why does the range of the function start from the minimum value of 5-5?
  3. What would change in the domain or range if the quadratic function opened downwards?
  4. Can the range of a quadratic function ever include negative infinity?
  5. How would transformations affect the domain and range of a quadratic function?

Tip: The domain of most polynomial functions (like quadratics) is always all real numbers unless specific restrictions are involved, such as square roots or division by zero.

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Math Problem Analysis

Mathematical Concepts

Quadratic Function
Domain and Range
Parabolas

Formulas

f(x) = a(x - h)^2 + k

Theorems

Vertex form of a quadratic equation

Suitable Grade Level

Grades 8-10