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How to fine the rang for f(x) and the rang for the inverse functon

How to fine the rang for f(x) and the rang for the inverse functon-example-1
User Efirvida
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1 Answer

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\begin{gathered} \text{range of f(x)= (-}\infty,0)\cup(0,\infty) \\ \text{range of f(x)=x}<0\text{ or x}>0 \\ \text{rangeof f}^(-1)(x)=(-\infty,1)\cup(1,\infty) \\ \text{rangeof f}^(-1)(x)=x<1\text{ or x}>1 \end{gathered}

Step-by-step explanation

Step 1

find the inverse of the function

a) let


y=(4)/(x^3-1)

now, swap the variables and isolate


\begin{gathered} y=(4)/(x^3-1)\leftrightarrow x=(4)/(y^3-1) \\ \end{gathered}
\begin{gathered} x=(4)/(y^3-1) \\ x(y^3-1)=4 \\ y^3-1=(4)/(x) \\ y^3=(4)/(x)+1 \\ y=\sqrt[3]{(4)/(x)+1} \\ \end{gathered}

find the DOMAIN of the inverse, this would be the range for f(x)

so


\begin{gathered} y=\sqrt[3]{(4)/(x)+1} \\ \text{the function is defined in all ream numbers, except when x= 0} \\ so \\ \text{domain of inverse: (-}\infty,0)\cup(0,\infty) \end{gathered}

therefore, the range of f(x)


\begin{gathered} \text{range of f(x)= (-}\infty,0)\cup(0,\infty) \\ \text{range of f(x)=x}<0\text{ or x}>0 \end{gathered}

Step 2

Now, as the range of a functino is the domain of its inverse,

the range of the inverse will be the domain of f(x), hence

a) find the domain of f(x)


y=(4)/(x^3-1)

the domains is all real numbers except the number/s that make the denominator equals zero,s o


\begin{gathered} x^3-1=0 \\ x^3=1 \\ x=1 \end{gathered}

therefore, the range of the inverse function is


\begin{gathered} \text{domain f(x)=rangeof f}^(-1)(x) \\ \text{rangeof f}^(-1)(x)=(-\infty,1)\cup(1,\infty) \\ \text{rangeof f}^(-1)(x)=x<1\text{ or x}>1 \end{gathered}

I hope this helps you

User Daniel Loiterton
by
5.3k points
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