Let ƒ(x)=x2+3 and g(x)=-2x+6. Find each of the following. (ƒ+g)(3)
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- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
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3. Functions
Function Composition
Problem 17
Textbook Question
Let ƒ(x)=x2+3 and g(x)=-2x+6. Find each of the following. (ƒ/g)(-1)
Verified step by step guidance1
Understand that the notation (ƒ/g)(x) means the function ƒ(x) divided by the function g(x), so (ƒ/g)(x) = \frac{ƒ(x)}{g(x)}.
Substitute the given functions into the expression: (ƒ/g)(x) = \frac{x^2 + 3}{-2x + 6}.
Replace x with -1 in both the numerator and the denominator: numerator = (-1)^2 + 3, denominator = -2(-1) + 6.
Calculate the values inside the numerator and denominator separately: numerator = 1 + 3, denominator = 2 + 6.
Write the final expression as a fraction using these values: (ƒ/g)(-1) = \frac{1 + 3}{2 + 6}.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Function Notation and Evaluation
Function notation, such as ƒ(x), represents a rule that assigns each input x to an output value. Evaluating a function at a specific value means substituting that value into the function's expression and simplifying to find the output.
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Evaluating Composed Functions
Function Division (Quotient of Functions)
The quotient of two functions (ƒ/g)(x) is defined as ƒ(x) divided by g(x), provided g(x) ≠ 0. To find (ƒ/g)(-1), evaluate both ƒ(-1) and g(-1) separately, then divide the results.
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Multiplying & Dividing Functions
Domain Restrictions in Function Operations
When dividing functions, the domain excludes values where the denominator function equals zero, as division by zero is undefined. It's important to check g(x) ≠ 0 before evaluating (ƒ/g)(x) at a given point.
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Domain Restrictions of Composed Functions
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