Math Problem Statement

What is the domain and range of y=1+x/5-x

Solution

The function given is:

y=1+x5xy = \frac{1 + x}{5 - x}

Domain:

The domain of a function consists of all values of xx for which the function is defined. In this case, the function is undefined when the denominator equals zero. To find when the denominator is zero:

5x=05 - x = 0

x=5x = 5

Thus, the function is undefined at x=5x = 5. Therefore, the domain is all real numbers except x=5x = 5. In interval notation, the domain is:

Domain=(,5)(5,)\text{Domain} = (-\infty, 5) \cup (5, \infty)

Range:

The range of the function refers to all possible values of yy. To find the range, let's manipulate the equation and solve for xx in terms of yy:

y=1+x5xy = \frac{1 + x}{5 - x}

Multiply both sides by 5x5 - x:

y(5x)=1+xy(5 - x) = 1 + x

Distribute yy:

5yxy=1+x5y - xy = 1 + x

Group terms involving xx on one side:

5y1=x+xy5y - 1 = x + xy

Factor out xx on the right-hand side:

5y1=x(1+y)5y - 1 = x(1 + y)

Now, solve for xx:

x=5y11+yx = \frac{5y - 1}{1 + y}

For xx to be defined, the denominator 1+y1 + y cannot be zero, which gives y=1y = -1. Therefore, the function is undefined when y=1y = -1.

Thus, the range is all real numbers except y=1y = -1. In interval notation, the range is:

Range=(,1)(1,)\text{Range} = (-\infty, -1) \cup (-1, \infty)

Summary:

  • Domain: (,5)(5,)(-\infty, 5) \cup (5, \infty)
  • Range: (,1)(1,)(-\infty, -1) \cup (-1, \infty)

Would you like further details or have any questions?

Here are some related questions you might want to explore:

  1. How can the vertical asymptote of this function be determined?
  2. What happens to yy as xx \to \infty?
  3. What is the horizontal asymptote of this function?
  4. How would you find the intercepts of this function?
  5. What is the behavior of this function around x=5x = 5?

Tip: The vertical asymptote occurs where the function's denominator is zero.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Domain and Range

Formulas

y = (1 + x) / (5 - x)
Domain: Denominator ≠ 0
Range: Solve for x in terms of y

Theorems

Domain theorem for rational functions
Range determination via solving

Suitable Grade Level

Grades 9-12