Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
3. Functions
Function Composition
Problem 81c
Textbook Question
Find the inverse of f(x)=(x−10)/(x+10).
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Step 1: To find the inverse of a function, we first replace the function notation f(x) with y. So, we rewrite the function as y = (x - 10) / (x + 10).
Step 2: The next step in finding the inverse of a function is to swap x and y. This gives us x = (y - 10) / (y + 10).
Step 3: Now, we need to solve this equation for y. To do this, we first multiply both sides by (y + 10) to get rid of the denominator on the right side. This gives us x(y + 10) = y - 10.
Step 4: Distribute x on the left side to get xy + 10x = y - 10. Then, rearrange the equation to get all terms involving y on one side and constants on the other. This gives us xy - y = -10 - 10x.
Step 5: Factor out y on the left side to get y(x - 1) = -10 - 10x. Finally, divide both sides by (x - 1) to solve for y. This gives us y = (-10 - 10x) / (x - 1), which is the inverse of the original function.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Function Inverses
An inverse function essentially reverses the effect of the original function. If f(x) takes an input x and produces an output y, then the inverse function, denoted as f⁻¹(y), takes y back to x. To find the inverse, one typically swaps the roles of x and y in the equation and solves for y.
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Rational Functions
A rational function is a function that can be expressed as the ratio of two polynomials. In the case of f(x) = (x - 10)/(x + 10), both the numerator and denominator are linear polynomials. Understanding the properties of rational functions, such as their domain and asymptotic behavior, is crucial for analyzing their inverses.
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Algebraic Manipulation
Algebraic manipulation involves rearranging and simplifying equations to isolate variables. This skill is essential when finding inverses, as it often requires moving terms across the equation, factoring, or using operations like addition, subtraction, multiplication, and division to solve for the desired variable.
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