Q. Find the derivative of \(e^{\frac{1}{x}}\).
Answer
Let \(f(x)=e^{1/x}\). Using the chain rule, the derivative is the derivative of the outer function times the derivative of the inner function:
\[
\frac{d}{dx}\left(e^{1/x}\right)=e^{1/x}\cdot \frac{d}{dx}\left(\frac{1}{x}\right)
\]
\[
\frac{d}{dx}\left(\frac{1}{x}\right)=-\frac{1}{x^2}
\]
So, the final result is:
\[
\frac{d}{dx}\left(e^{1/x}\right)=-\frac{e^{1/x}}{x^2}
\]
Detailed Explanation
We want to find the derivative of the function
\[
f(x)=e^{\frac{1}{x}}.
\]
This is a composite function, so we will use the Chain Rule.
Step 1: Identify the outer and inner functions.
Rewrite the expression as
\[
f(x)=\exp\!\left(g(x)\right)
\]
where the outer function is
\[
\exp(u)=e^{u}
\]
and the inner function is
\[
g(x)=\frac{1}{x}.
\]
Step 2: Differentiate the outer function.
The derivative of \(e^{u}\) with respect to \(u\) is
\[
\frac{d}{du}\left(e^{u}\right)=e^{u}.
\]
Step 3: Differentiate the inner function.
Now compute the derivative of \(g(x)=\frac{1}{x}=x^{-1}\):
\[
g'(x)=\frac{d}{dx}\left(x^{-1}\right)=-x^{-2}=-\frac{1}{x^{2}}.
\]
Step 4: Apply the Chain Rule.
The Chain Rule says:
\[
\frac{d}{dx}\left(e^{g(x)}\right)=e^{g(x)}\cdot g'(x).
\]
Substitute \(g(x)=\frac{1}{x}\) and \(g'(x)=-\frac{1}{x^{2}}\):
\[
f'(x)=e^{\frac{1}{x}}\left(-\frac{1}{x^{2}}\right).
\]
Final Answer:
\[
\frac{d}{dx}\left(e^{\frac{1}{x}}\right)=-\frac{1}{x^{2}}\,e^{\frac{1}{x}}.
\]
Graph
Calculus FAQ
What is the derivative of \(e^{1/x}\)?
Why do we use the chain rule here?
What is \(\frac{d}{dx}\left(\frac{1}{x}\right)\)?
What is the derivative of \(e^{a/x}\) for constant \(a\)?
What is the derivative of \(\left(e^{1/x}\right)^{-1}\) or \(e^{-1/x}\)?
What is the domain of the derivative?
What is the second derivative of \(e^{1/x}\)?
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