Consider the function

MATHEMATICS · Multi-part · AP · Calculus BC · Infinite Sequences and Series · Infinite Sequences and Series

Problem

Consider the function g(x)=sin⁡xg(x)=\sin x. A degree-5 Maclaurin polynomial is used to approximate gg at x=0.5x=0.5. A calculator gives sin⁡(0.5)≈0.4794\sin(0.5)\approx0.4794. (a) Derive the degree-5 Maclaurin polynomial P5(x)P_{5}(x) for sin⁡x\sin x. (b) Evaluate P5(0.5)P_{5}(0.5), expressing your answer to six decimal places. (c) Establish an upper bound for the magnitude of the remainder when P5(0.5)P_{5}(0.5) is used to approximate sin⁡(0.5)\sin(0.5). Present clear justification for every inequality you use. (d) Compute the actual error ∣sin⁡(0.5)−P5(0.5)∣|\sin(0.5)-P_{5}(0.5)|. Compare this value with the bound obtained in part (c) and discuss whether the bound is sharp or conservative.

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