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Ch. 4 - Inverse, Exponential, and Logarithmic Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 5, Problem 114

Write an equation for the inverse function of each one-to-one function given. ƒ(x) = 4x+2

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Start with the given function: \(f(x) = 4^{x} + 2\).
To find the inverse function, first replace \(f(x)\) with \(y\): \(y = 4^{x} + 2\).
Swap the variables \(x\) and \(y\) to reflect the inverse relationship: \(x = 4^{y} + 2\).
Isolate the exponential term by subtracting 2 from both sides: \(x - 2 = 4^{y}\).
Take the logarithm base 4 of both sides to solve for \(y\): \(y = \log_{4}(x - 2)\), which gives the inverse function \(f^{-1}(x) = \log_{4}(x - 2)\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

One-to-One Functions

A one-to-one function is a function where each output corresponds to exactly one input, ensuring it has an inverse. This property is essential because only one-to-one functions have inverses that are also functions. Verifying this helps confirm that the inverse function exists.
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Inverse Functions

An inverse function reverses the effect of the original function, swapping inputs and outputs. To find the inverse, you replace f(x) with y, interchange x and y, and then solve for y. The inverse function essentially 'undoes' the original function's operation.
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Graphing Logarithmic Functions

Exponential and Logarithmic Functions

Since the given function involves an exponential expression (4^(x+2)), its inverse will involve logarithms. Understanding that logarithms are the inverses of exponential functions is crucial for solving for the inverse function. Specifically, the inverse uses the logarithm base 4 to isolate the variable.
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Graphs of Logarithmic Functions