#Taylor series and Taylor's inequality

8 messages · Page 1 of 1 (latest)

rotund wagon
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So I have the Maclaurin series $$T_5 (x)=\sqrt{x+1}\approx1+\frac1{2}x-\frac1{8}x^2+\frac1{16}x^3-\frac{5}{128}x^4+\frac{7}{256}x^5$$ where $$f^{(6)}(x)=-\frac{945}{64(x+1)^{\frac{11}{2}}}.$$ I'm trying to find the error between $x\in[0,0.5]$ and $x\in[-0.5,0]$. \ So for $x\in[0,0,5]$ it's an alternating series so I used the error estimate for that, $$\abs{s-s_n}\le a_{n+1}=\abs{-\frac{21}{1024}(0.5)^6}\approx 3.2\times 10^{-4}.$$ While for $x\in[-0.5,0]$ you'd use Taylor's inequality, so, $$\abs{E_5 (x)}\le \abs{\frac{f^{n+1}(z)}{(n+1)!}x^{n+1}}=\abs{\frac{f^6(-0.5)}{6!}(-0.5)^6}\approx 0.015$$

slim rivetBOT
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lyric trellisBOT
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Anonymous

rotund wagon
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Does my working look right here?

vagrant socket
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yeah pretty much

rotund wagon
tacit sentinelBOT
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@rotund wagon has given 1 rep to @vagrant socket