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IntroductionTogethighaccuracynumericalsolutionsofstiffdifferentialequations,weneedhighordernumericalmethodswhicharegoodinstability.Considerfollowingstiffdifferentialequations:y′=f(t,y), y(a)=η (t∈[a,b]),(1)wherey=( 1y, 2y,…, Ny)T. Assumethesolution… 相似文献
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By the discussion of the formula and properties of (4,4) parametric form rational approximation to function exp(q), the fourth order derivative one-step exponentially fitted method and the third order derivative hybrid one-step exponentially
fitted method are presented, their order p satisfying 6≤p≤8. The necessary and sufficient conditions for the two methods to
be A-stable are given. Finally, for the fourth order derivative method, the error bound and the necessary and sufficient conditions
for it to be median are discussed.
Foundation item: the Science Technology Foundation of Ministry of Machine-Building Industry of China (96252011) 相似文献
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学生用等价无穷小代换求极限的过程中出现许多我们认为是错误的方法,但有些错误的方法又能够得到正确的结论,如求极限时对复合函数的中间变量作等价无穷小代换;两非等价无穷小和差分别做等价无穷小代换等,这应该算对还是错?本文在理论上作了分析. 相似文献
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利用洛必达法则与等价无穷小代换对抽象函数的00型极限可得结论:设当x→x0时f(x)与g(x)为无穷小,g(x)~(x-x0)β,取k为正实数,使得fk(x)=A(x-x0)α+o[(x-x0)α],其中A0,α≥2,β0为实数,则有limx→x0f(x)g(x)=1.该方法对求常见的00型极限都适用.当使用洛必达法则求li mx→x0f(x)g(x)很复杂时,使用该方法可简化计算. 相似文献