Math  /  Algebra

QuestionFind a formula for the inverse of the following function, if possible. s(x)=4x53s(x)=\sqrt[3]{4 x-5}
Answer How to enter your answer (opens in new window)
Selecting a radio button will replace the entered answer value(s) with the radio button value. If the radio button is not selected, the entered answer is used. s1(x)=s^{-1}(x)= does not have an inverse function

Studdy Solution

STEP 1

What is this asking? We're on a mission to find the inverse function of a cube root function, which means we want to discover a function that *undoes* the original function's actions! Watch out! Don't forget that not every function has an inverse.
A function has an inverse if and only if it's a one-to-one function.
Luckily, cube root functions are one-to-one!

STEP 2

1. Set up the inverse function.
2. Solve for the inverse.

STEP 3

Let's start by replacing s(x)s(x) with yy to make things a bit easier to work with.
So, we have: y=4x53y = \sqrt[3]{4x - 5} This is just a cosmetic change to make our calculations easier to read.

STEP 4

To find the inverse, we **swap** xx and yy.
This gives us: x=4y53x = \sqrt[3]{4y - 5} This swap is the core action of finding an inverse function.
It reflects the fact that the input of the inverse is the output of the original, and vice-versa.

STEP 5

Now, we want to solve for yy.
Let's **cube both sides** of the equation to get rid of the cube root: x3=(4y53)3x^3 = (\sqrt[3]{4y - 5})^3 x3=4y5x^3 = 4y - 5Cubing both sides is the inverse operation of taking the cube root, and it allows us to isolate the expression inside the cube root.

STEP 6

We're almost there! **Add** 5\textbf{5} to both sides: x3+5=4yx^3 + 5 = 4y Now, **divide** both sides by 4\textbf{4} to isolate yy: x3+54=y\frac{x^3 + 5}{4} = y

STEP 7

Finally, we rewrite this as the inverse function: s1(x)=x3+54s^{-1}(x) = \frac{x^3 + 5}{4} This is our final inverse function!
It takes an input xx, cubes it, adds 5, and then divides the result by 4.

STEP 8

The inverse function is: s1(x)=x3+54s^{-1}(x) = \frac{x^3 + 5}{4}

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