Identify Function & Expansion Point: Identify the function and the point of expansion.We are given the function f(x)=ln(x) and we need to find the third-degree Taylor polynomial (P3) centered at c=2.
Calculate First Derivative: Calculate the first derivative of f(x). The first derivative of f(x)=ln(x) is f′(x)=x1. We evaluate this at x=2 to get f′(2)=21.
Calculate Second Derivative: Calculate the second derivative of f(x).The second derivative of f′(x)=x1 is f′′(x)=−x21. We evaluate this at x=2 to get f′′(2)=−41.
Calculate Third Derivative: Calculate the third derivative of f(x). The third derivative of f′′(x)=−x21 is f(x)=x32. We evaluate this at x=2 to get f(2)=82=41.
Write Taylor Polynomial Formula: Write down the formula for the third-degree Taylor polynomial.The third-degree Taylor polynomial is given by:P3(x)=f(c)+f′(c)(x−c)+2!f′′(c)(x−c)2+3!f(c)(x−c)3
Substitute Values: Substitute the values into the Taylor polynomial formula.Using the values from the previous steps, we get:P3(x)=ln(2)+(21)(x−2)−(41)2!(x−2)2+(41)3!(x−2)3
Simplify Polynomial: Simplify the polynomial. P3(x)=ln(2)+(21)(x−2)−(81)(x−2)2+(241)(x−2)3This is the third-degree Taylor polynomial for f(x)=ln(x) centered at c=2.
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