Questions: If f(2)=4 and f'(2)=3/4, use the formula (f^(-1))'(x)=1/f'(f^(-1)(x)) to find (f^(-1))'(4).
(f^(-1))'(4)=
Transcript text: If $f(2)=4$ and $f^{\prime}(2)=\frac{3}{4}$, use the formula $\left(f^{-1}\right)^{\prime}(x)=\frac{1}{f^{\prime}\left(f^{-1}(x)\right)}$ to find $\left(f^{-1}\right)^{\prime}(4)$.
\[
\left(f^{-1}\right)^{\prime}(4)=
\]
Solution
Solution Steps
To find \(\left(f^{-1}\right)^{\prime}(4)\), we use the formula \(\left(f^{-1}\right)^{\prime}(x)=\frac{1}{f^{\prime}\left(f^{-1}(x)\right)}\). Since \(f(2) = 4\), it follows that \(f^{-1}(4) = 2\). We then substitute \(f^{-1}(4) = 2\) into the formula to get \(\left(f^{-1}\right)^{\prime}(4) = \frac{1}{f^{\prime}(2)}\). Given \(f^{\prime}(2) = \frac{3}{4}\), we can calculate \(\left(f^{-1}\right)^{\prime}(4)\).
Step 1: Identify the Inverse Function Derivative Formula
To find \(\left(f^{-1}\right)^{\prime}(4)\), we use the formula:
\[
\left(f^{-1}\right)^{\prime}(x) = \frac{1}{f^{\prime}\left(f^{-1}(x)\right)}
\]
Step 2: Determine \(f^{-1}(4)\)
Since \(f(2) = 4\), it follows that:
\[
f^{-1}(4) = 2
\]
Step 3: Substitute into the Derivative Formula
Now, we substitute \(f^{-1}(4) = 2\) into the derivative formula:
\[
\left(f^{-1}\right)^{\prime}(4) = \frac{1}{f^{\prime}(2)}
\]
Step 4: Use the Given Derivative Value
We know that \(f^{\prime}(2) = \frac{3}{4}\). Therefore, we can calculate:
\[
\left(f^{-1}\right)^{\prime}(4) = \frac{1}{\frac{3}{4}} = \frac{4}{3}
\]