Math Problem Statement

For the questions below, enter your answers using interval notation. You can use "U" to represent a "union", e.g. enter "(1,2) U (3,5)" for (1,2)∪(3,5). You can enter "oo" for ∞, e.g. enter "(-oo, oo)" for (−∞,∞)

.

You may graph f(x) and g(x)

on Desmos to help determine their ranges.

Suppose f(x)=3x^2+4

.

What is the domain of f

?

What is the range of f

?

Suppose g(x)=√x−4/(x−10)

.

What is the domain of g

?

What is the range of g

?

Solution

Let's go through the problems one by one:

1. Domain of f(x)=3x2+4f(x) = 3x^2 + 4

The function f(x)=3x2+4f(x) = 3x^2 + 4 is a quadratic function, and quadratic functions have a domain of all real numbers. This is because there are no restrictions on the input xx (no division by zero or square roots of negative numbers).

Domain of f(x)f(x): (,)(-\infty, \infty)

2. Range of f(x)=3x2+4f(x) = 3x^2 + 4

This is a parabola opening upwards (since the coefficient of x2x^2 is positive). The minimum value of the function occurs when x=0x = 0, giving us: f(0)=3(0)2+4=4f(0) = 3(0)^2 + 4 = 4 Since the parabola opens upwards, the range of f(x)f(x) starts at 4 and goes to infinity.

Range of f(x)f(x): [4,)[4, \infty)

3. Domain of g(x)=x4x10g(x) = \frac{\sqrt{x - 4}}{x - 10}

For g(x)g(x), we need to look at two restrictions:

  • The square root function x4\sqrt{x - 4} requires that x40x - 4 \geq 0, so x4x \geq 4.
  • The denominator x10x - 10 cannot be zero, so x10x \neq 10.

Therefore, the domain is all x4x \geq 4 except x=10x = 10.

Domain of g(x)g(x): [4,10)(10,)[4, 10) \cup (10, \infty)

4. Range of g(x)=x4x10g(x) = \frac{\sqrt{x - 4}}{x - 10}

The function has a square root in the numerator and a linear expression in the denominator. As x4+x \to 4^+, g(x)0g(x) \to 0, and as xx \to \infty, the behavior of the function will depend on the balance between the square root in the numerator and the linear term in the denominator. The function does not have a simple maximum or minimum, but we can deduce that the range is all real numbers except 0.

Range of g(x)g(x): (,0)(0,)(-\infty, 0) \cup (0, \infty)


Would you like more detailed explanations on any of these steps? Here are some related questions to explore:

  1. What happens to the domain and range of f(x)f(x) if you change the constant term (e.g., from +4 to -4)?
  2. How would you graph the function g(x)=x4x10g(x) = \frac{\sqrt{x - 4}}{x - 10} to confirm its domain and range visually?
  3. Can you find the horizontal asymptote of g(x)g(x)?
  4. What would happen to the domain of g(x)g(x) if we changed the denominator to x+10x + 10?
  5. How does the range of a function like f(x)=3x2+4f(x) = 3x^2 + 4 change if we add a negative sign in front of the x2x^2 term?

Tip: When dealing with square roots or denominators, always check the conditions for valid inputs (such as non-negative values for square roots and non-zero values for denominators).

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Math Problem Analysis

Mathematical Concepts

Functions
Domain and Range
Quadratic Functions
Radical Functions

Formulas

f(x) = 3x^2 + 4
g(x) = √(x - 4) / (x - 10)

Theorems

Domain of a function: all real numbers except where function is undefined
Range of a quadratic function
Domain restrictions for square roots and denominators

Suitable Grade Level

Grades 9-11