Find the number c that satisfies the conclusion of the Mean Value Theorem on the given interval. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.) f ( x ) = √ x , [ 0 , 9 ]

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Answer:

[tex]c= \dfrac{9}{4}[/tex]

Step-by-step explanation:

For a function f(x) to satisfy the Mean Value Theorem, it must satisfy the following conditions:

  • Be defined and continuous on the interval [a,b]
  • Be differentiable on (a,b)
  • There is at least one number c in the interval (a,b) (that is a < c < b) such that [tex]f'(c)=\dfrac{f(b)-f(a)}{b-a}[/tex]

Given [tex]f(x)=\sqrt{x}$ in [0,9][/tex]

1. f(x) is defined and continuous on [0,9] since a polynomial function is continuous everywhere.

2. f(x) is differentiable in the interval (0,9) since a polynomial function is differentiable everywhere.

[tex]f(9)=\sqrt{9}=3\\f(0)=\sqrt{0}=0\\f'(x)=\dfrac{1}{2\sqrt{x} }[/tex]

3.By the mean value theorem:

[tex]f'(c) = \displaystyle\frac{f(b)-f(a)}{b-a}\\\\\frac{1}{2\sqrt{c}} = \frac{f(9) - f(0)}{9-0} = \frac{3}{9}\\\\\frac{1}{2\sqrt{c}} = \frac{1}{3}\\\\$Cross multiply$\\\\2\sqrt{c}=3\\\\$Square both sides$\\\\(2\sqrt{c})^2=3^2\\\\4c=9\\\\c= \dfrac{9}{4}[/tex]