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Worksheet LT 7 Sample Quiz

1.

Suppose you know that the function \(f\) passes through the point \((4,3)\) and has first derivative
\begin{equation*} f'(x) = \sqrt{x}+ 5. \end{equation*}

(a)

Find the equation of the tangent line to the the function \(f(x)\) at the point \((4,3)\text{.}\)

(b)

Use the tangent line (or the equivalent local linearization) to approximate \(f(4.1)\text{.}\) Show your work.

(c)

Suppose you found out that \(f''(4) = 0.25\text{.}\) What does this tell you about the shape of \(f\) near \(x = 4\text{?}\) Does this mean your approximation for \(f(4.1)\) is an over estimate or under estimate? Briefly explain.