Problem

Find the absolute maximum and minimum values of the function over the indicated interval, and indicate the $x$-values at which they occur.
\[
f(x)=x+\frac{1}{x} ;[1,25]
\]
The absolute maximum value is $\frac{626}{25}$ at $x=25$.
(Use a comma to separate answers as needed.)
The absolute minimum value is at $x=$ (Use a comma to separate answers as needed.)

Answer

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Answer

\(\boxed{\text{Final Answer: The absolute maximum value is }\frac{626}{25}\text{ at }x=25\text{. The absolute minimum value is }2\text{ at }x=1.}\)

Steps

Step 1 :The function given is \(f(x)=x+\frac{1}{x}\) and we are to find the absolute maximum and minimum values of the function over the interval [1,25].

Step 2 :The function is continuous and differentiable on the interval [1,25]. Therefore, the absolute maximum and minimum values of the function occur either at the endpoints of the interval or at critical points in the interval.

Step 3 :To find the critical points, we need to find the derivative of the function and set it equal to zero. The derivative of the function \(f(x)=x+\frac{1}{x}\) is \(f'(x)=1-\frac{1}{x^2}\).

Step 4 :Setting this equal to zero gives \(x^2=1\), so \(x=\pm1\). However, only \(x=1\) is in the interval [1,25].

Step 5 :We then evaluate the function at the endpoints of the interval and at the critical point to find the absolute maximum and minimum values.

Step 6 :At \(x=1\), \(f(x)=1+\frac{1}{1}=2\).

Step 7 :At \(x=25\), \(f(x)=25+\frac{1}{25}=\frac{626}{25}\).

Step 8 :Comparing these values, we find that the absolute maximum value is \(\frac{626}{25}\) at \(x=25\) and the absolute minimum value is \(2\) at \(x=1\).

Step 9 :\(\boxed{\text{Final Answer: The absolute maximum value is }\frac{626}{25}\text{ at }x=25\text{. The absolute minimum value is }2\text{ at }x=1.}\)

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