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Questions: Algebra BusinessCalculus
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Find the linear approximation of \(\displaystyle f(x) = \sqrt{x + 9}\) at \(\displaystyle a = 0\) and use it to approximate \(\displaystyle \sqrt{8.71}\)
Using the formula for the linearization \(\displaystyle L(x) = f'(a)(x-a)+f(a)\) gives: \begin{equation*}f(x) = \sqrt{x + 9} \approx L(x) = \frac{x}{6} + 3 \end{equation*} To approximate \(\displaystyle \sqrt{8.71}\) use \(\displaystyle x = 8.71-9 = -0.29\). \begin{equation*}\sqrt{8.71} = f(-0.29) \approx L(-0.29) = 2.951667 \end{equation*}
\begin{question}Find the linear approximation of $f(x) = \sqrt{x + 9}$ at $a = 0$ and use it to approximate $\sqrt{8.71}$ \soln{9cm}{Using the formula for the linearization $L(x) = f'(a)(x-a)+f(a)$ gives: \begin{equation*}f(x) = \sqrt{x + 9} \approx L(x) = \frac{x}{6} + 3 \end{equation*} To approximate $\sqrt{8.71}$ use $x = 8.71-9 = -0.29$. \begin{equation*}\sqrt{8.71} = f(-0.29) \approx L(-0.29) = 2.951667 \end{equation*} } \end{question}
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<p> <p>Find the linear approximation of <img class="equation_image" title=" \displaystyle f(x) = \sqrt{x + 9} " src="/equation_images/%20%5Cdisplaystyle%20f%28x%29%20%3D%20%5Csqrt%7Bx%20%2B%209%7D%20" alt="LaTeX: \displaystyle f(x) = \sqrt{x + 9} " data-equation-content=" \displaystyle f(x) = \sqrt{x + 9} " /> at <img class="equation_image" title=" \displaystyle a = 0 " src="/equation_images/%20%5Cdisplaystyle%20a%20%3D%200%20" alt="LaTeX: \displaystyle a = 0 " data-equation-content=" \displaystyle a = 0 " /> and use it to approximate <img class="equation_image" title=" \displaystyle \sqrt{8.71} " src="/equation_images/%20%5Cdisplaystyle%20%5Csqrt%7B8.71%7D%20" alt="LaTeX: \displaystyle \sqrt{8.71} " data-equation-content=" \displaystyle \sqrt{8.71} " /> </p> </p>
<p> <p>Using the formula for the linearization <img class="equation_image" title=" \displaystyle L(x) = f'(a)(x-a)+f(a) " src="/equation_images/%20%5Cdisplaystyle%20L%28x%29%20%3D%20f%27%28a%29%28x-a%29%2Bf%28a%29%20" alt="LaTeX: \displaystyle L(x) = f'(a)(x-a)+f(a) " data-equation-content=" \displaystyle L(x) = f'(a)(x-a)+f(a) " /> gives:
<img class="equation_image" title=" f(x) = \sqrt{x + 9} \approx L(x) = \frac{x}{6} + 3 " src="/equation_images/%20f%28x%29%20%3D%20%5Csqrt%7Bx%20%2B%209%7D%20%5Capprox%20L%28x%29%20%3D%20%5Cfrac%7Bx%7D%7B6%7D%20%2B%203%20%20" alt="LaTeX: f(x) = \sqrt{x + 9} \approx L(x) = \frac{x}{6} + 3 " data-equation-content=" f(x) = \sqrt{x + 9} \approx L(x) = \frac{x}{6} + 3 " />
To approximate <img class="equation_image" title=" \displaystyle \sqrt{8.71} " src="/equation_images/%20%5Cdisplaystyle%20%5Csqrt%7B8.71%7D%20" alt="LaTeX: \displaystyle \sqrt{8.71} " data-equation-content=" \displaystyle \sqrt{8.71} " /> use <img class="equation_image" title=" \displaystyle x = 8.71-9 = -0.29 " src="/equation_images/%20%5Cdisplaystyle%20x%20%3D%208.71-9%20%3D%20-0.29%20" alt="LaTeX: \displaystyle x = 8.71-9 = -0.29 " data-equation-content=" \displaystyle x = 8.71-9 = -0.29 " /> .
<img class="equation_image" title=" \sqrt{8.71} = f(-0.29) \approx L(-0.29) = 2.951667 " src="/equation_images/%20%5Csqrt%7B8.71%7D%20%3D%20f%28-0.29%29%20%20%5Capprox%20L%28-0.29%29%20%3D%202.951667%20%20" alt="LaTeX: \sqrt{8.71} = f(-0.29) \approx L(-0.29) = 2.951667 " data-equation-content=" \sqrt{8.71} = f(-0.29) \approx L(-0.29) = 2.951667 " />
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