■e^e (その2)
【1】4次近似
a=2またはa=3として,テイラー展開
exp(x)=exp(a){1+(x−a)+(x−a)^2/2+(x−a)^3/6+・・・}
の誤差項Rを1未満に抑えることを考える.
R<exp(a)/n!<1
n!>exp(a)
より,4次近似
exp(x)=exp(a){1+(x−a)+(x−a)^2/2+(x−a)^3/6+(x−a)^4/24}
を採用したい.
[1]x=2.7,a=2 → 14.868
[2]x=2.7,a=3 → 14.8801
[3]x=2.8,a=2 → 16.4214
[4]x=2.8,a=3 → 16.4447
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【2】5次近似
exp(x)=exp(a){1+(x−a)+(x−a)^2/2+(x−a)^3/6+(x−a)^4/24+(x−a)^5/120}
[1]x=2.7,a=2 → 14.8784
[2]x=2.7,a=3 → 14.8797
[3]x=2.8,a=2 → 16.4416
[4]x=2.8,a=3 → 16.4446
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【3】3次近似
exp(x)=exp(a){1+(x−a)+(x−a)^2/2+(x−a)^3/6}
[1]x=2.7,a=2 → 14.7941
[2]x=2.7,a=3 → 14.8733
[3]x=2.8,a=2 → 16.2953
[4]x=2.8,a=3 → 16.4433
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【4】2次近似
exp(x)=exp(a){1+(x−a)+(x−a)^2/2}
[1]x=2.7,a=2 → 14.3717
[2]x=2.7,a=3 → 14.9637
[3]x=2.8,a=2 → 15.6647
[4]x=2.8,a=3 → 16.4701
===================================
【5】1次近似
exp(x)=exp(a){1+(x−a)}
[1]x=2.7,a=2 → 12.5614
[2]x=2.7,a=3 → 14.0599
[3]x=2.8,a=2 → 13.3003
[4]x=2.8,a=3 → 16.0684
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