Math Problem Statement

Number 7

In Exercises 5-8, find formulas for f/g and g/f. Give the domain of each. (Focus on Exercise 7)

Solution

For problem 7 in the image you provided, you're asked to find the formulas for f/gf/g and g/fg/f, as well as to determine the domain of each function.

Given Functions:

f(x)=1x2f(x) = \sqrt{1 - x^2} g(x)=1xg(x) = \sqrt{1 - x}

1. Finding f(x)g(x)\frac{f(x)}{g(x)}:

f(x)g(x)=1x21x\frac{f(x)}{g(x)} = \frac{\sqrt{1 - x^2}}{\sqrt{1 - x}}

This can be simplified by recognizing that the square roots can be combined:

f(x)g(x)=1x21x\frac{f(x)}{g(x)} = \sqrt{\frac{1 - x^2}{1 - x}}

2. Finding g(x)f(x)\frac{g(x)}{f(x)}:

g(x)f(x)=1x1x2\frac{g(x)}{f(x)} = \frac{\sqrt{1 - x}}{\sqrt{1 - x^2}}

Similarly, this simplifies to:

g(x)f(x)=1x1x2\frac{g(x)}{f(x)} = \sqrt{\frac{1 - x}{1 - x^2}}

3. Determining the Domain:

For f(x)g(x)\frac{f(x)}{g(x)}:

  • The expression inside the square roots must be non-negative.
  • For f(x)=1x2f(x) = \sqrt{1 - x^2}, 1x201 - x^2 \geq 0, which means 1x1-1 \leq x \leq 1.
  • For g(x)=1xg(x) = \sqrt{1 - x}, 1x01 - x \geq 0, which means x1x \leq 1.

Thus, the domain of f(x)g(x)\frac{f(x)}{g(x)} is where both conditions are true, i.e., 1x1-1 \leq x \leq 1.

However, there's an additional condition: 1x1 - x must not be zero, because that would make the denominator of f(x)g(x)\frac{f(x)}{g(x)} zero. Thus, x1x \neq 1.

Domain of f(x)g(x)\frac{f(x)}{g(x)}: 1x<1-1 \leq x < 1

For g(x)f(x)\frac{g(x)}{f(x)}:

  • Similar reasoning applies as above, with x=1x = 1 being excluded from the domain.

Domain of g(x)f(x)\frac{g(x)}{f(x)}: 1x<1-1 \leq x < 1

Summary:

  • Formula for f(x)g(x)\frac{f(x)}{g(x)}: 1x21x\sqrt{\frac{1 - x^2}{1 - x}}
  • Domain: 1x<1-1 \leq x < 1
  • Formula for g(x)f(x)\frac{g(x)}{f(x)}: 1x1x2\sqrt{\frac{1 - x}{1 - x^2}}
  • Domain: 1x<1-1 \leq x < 1

Would you like to go over more details or have any questions? Here are some related questions you might consider:

  1. What happens to the function f(x)g(x)\frac{f(x)}{g(x)} as xx approaches 1?
  2. How would the domain change if the functions involved were slightly altered?
  3. Can you express f(x)g(x)\frac{f(x)}{g(x)} without a square root, and what would that imply about the domain?
  4. What would be the result of f(x)+g(x)f(x) + g(x) and its domain?
  5. How do the graphs of f(x)f(x) and g(x)g(x) behave individually over their domains?

Tip: Always check for points where the denominator could be zero when determining the domain of a function involving division.

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Square Roots
Domain and Range

Formulas

f(x) = sqrt(1 - x^2)
g(x) = sqrt(1 - x)
f/g = sqrt((1 - x^2)/(1 - x))
g/f = sqrt((1 - x)/(1 - x^2))

Theorems

Square Root Function
Domain Restrictions

Suitable Grade Level

Grades 9-12