Math Problem Statement

Find the domain and range of the following: (a). g(x) = x^2/x+x^2

Solution

Let's analyze the function g(x)=x2x+x2g(x) = \frac{x^2}{x + x^2} to determine its domain and range.

1. Domain:

The domain of a function is the set of all possible input values (x-values) for which the function is defined.

The function g(x)=x2x+x2g(x) = \frac{x^2}{x + x^2} is a rational function, which means it is defined as long as the denominator is not zero.

  • The denominator of g(x)g(x) is x+x2x + x^2. We need to find where this expression is equal to zero because the function is undefined at those points: x+x2=0x + x^2 = 0 Factor the expression: x(1+x)=0x(1 + x) = 0 This gives us two solutions: x=0or1+x=0x=1x = 0 \quad \text{or} \quad 1 + x = 0 \quad \Rightarrow \quad x = -1

Thus, the function is undefined at x=0x = 0 and x=1x = -1. The domain of g(x)g(x) excludes these points.

So, the domain is: Domain of g(x):R{1,0}\text{Domain of } g(x): \, \mathbb{R} \setminus \{-1, 0\} This means g(x)g(x) is defined for all real numbers except x=1x = -1 and x=0x = 0.

2. Range:

The range of a function is the set of all possible output values (y-values).

To find the range, let's analyze the behavior of the function.

  • First, simplify the function if possible: g(x)=x2x+x2=x2x(1+x)=x1+x,x0,1g(x) = \frac{x^2}{x + x^2} = \frac{x^2}{x(1 + x)} = \frac{x}{1 + x}, \quad x \neq 0, -1 The simplified form is g(x)=x1+xg(x) = \frac{x}{1 + x}.

  • Next, find the possible values of y=g(x)y = g(x) by solving for xx in terms of yy: y=x1+xy = \frac{x}{1 + x} Multiply both sides by 1+x1 + x: y(1+x)=xy(1 + x) = x Distribute yy: y+yx=xy + yx = x Rearrange to solve for xx: y+yxx=0y + yx - x = 0 Factor out xx:

    \quad \Rightarrow \quad x = \frac{-y}{y - 1}, \quad y \neq 1$$ For $$y = 1$$, check the function directly: $$1 = \frac{x}{1 + x}$$ $$1 + x = x$$ This leads to a contradiction, so $$y = 1$$ is not in the range.
  • g(x)g(x) can take all values except y=1y = 1.

Thus, the range of g(x)g(x) is: Range of g(x):R{1}\text{Range of } g(x): \, \mathbb{R} \setminus \{1\}

Summary:

  • Domain: R{1,0}\mathbb{R} \setminus \{-1, 0\}
  • Range: R{1}\mathbb{R} \setminus \{1\}

Would you like more details or have any questions?

Here are some related questions to consider:

  1. How would the range change if the function were g(x)=x2x+2x2g(x) = \frac{x^2}{x + 2x^2}?
  2. What happens to the domain if the function was g(x)=x2+1x+x2g(x) = \frac{x^2 + 1}{x + x^2}?
  3. What are the domain and range of the function g(x)=1x2+xg(x) = \frac{1}{x^2 + x}?
  4. How does the function g(x)=x2+xx+1g(x) = \frac{x^2 + x}{x + 1} behave at x=1x = -1?
  5. Can the range of a rational function be all real numbers? If so, under what conditions?

Tip: Simplifying the function first can often make finding the domain and range much easier!

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Domain and Range

Formulas

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Theorems

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Suitable Grade Level

Grades 11-12