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 Operations
Problem 36
Textbook Question
Find f+g, f−g, fg, and gf. Determine the domain for each function.
f(x)=6x2−x−1, g(x)=x−1
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1
To find \( (f+g)(x) \), add the functions \( f(x) \) and \( g(x) \): \( (f+g)(x) = f(x) + g(x) = (6x^2 - x - 1) + (x - 1) \). Combine like terms to simplify.
To find \( (f-g)(x) \), subtract \( g(x) \) from \( f(x) \): \( (f-g)(x) = f(x) - g(x) = (6x^2 - x - 1) - (x - 1) \). Distribute the negative sign and combine like terms.
To find \( (fg)(x) \), multiply the functions \( f(x) \) and \( g(x) \): \( (fg)(x) = f(x) \cdot g(x) = (6x^2 - x - 1)(x - 1) \). Use the distributive property (FOIL method) to expand the expression.
To find \( \left(\frac{f}{g}\right)(x) \), divide \( f(x) \) by \( g(x) \): \( \left(\frac{f}{g}\right)(x) = \frac{6x^2 - x - 1}{x - 1} \). Simplify the expression if possible by factoring the numerator and checking for common factors with the denominator.
Determine the domain for each function: For \( f+g \) and \( f-g \), the domain is all real numbers since there are no restrictions. For \( fg \), the domain is also all real numbers. For \( \frac{f}{g} \), the domain excludes \( x = 1 \) because it makes the denominator zero, which is undefined.
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