全部文献期刊学位论文会议报纸专利标准年鉴图书|学者科研项目
中外文文献  中文文献  外文文献
作者:Leif Mejlbro
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.321-331ZBMATH
摘要:In this paper is considered a new and ingenious approach of solving linear differential equations $$d^nx/dt^n+ a_{n-1} (t)d^{n-1} x/dt^{n-1}+ \cdots+ a_1(t)dx/dt +a_0(t)x =f(t),\ t\in I. \tag 1$$ This new method consists in writing the equation (1) in the form $$d/dt \Biggl\{1/p_...
作者:Sergio Invernizzi
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.357-365ZBMATH
摘要:The author proves that there exist vertical plane $C^1$ curves such that the classical Newton mechanics based on ordinary differential equations cannot uniquely determine the future motion of a particle sliding down under the effect of gravity. He gives as example a $C^1$ concave...
作者:M.A. Seoud , M.Z. Youssef
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.367-371ZBMATH
摘要:A graph $G=(V, E)$ is graceful if there is a function $f:V\to \{0,1,\dots,|E|\}$, such that each edge $\{v,w\}\in E$ gets a different value for $|f(v)-f(w)|$ from the set $\{1,\dots,|E|\}$. A graph $G= (V,E)$ is harmonious, if there is an injection $f:V\to\text{Z}_m$ such that th...
作者:G.R. Lindfield , J.E.T. Penny
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.427-436ZBMATH
摘要:The authors describe some MATLAB functions that allow computations with sparse matrices. This is not a complete description but rather a good didactic introduction to that topic.
作者:David E. Dobbs
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.447-451ZBMATH
摘要:Working within the Poincar\'e half-plane model for the hyperbolic plane, the author gives in this Classroom Note a short proof that each real number $d$, such that $0...
作者:Kazuaki Kitahara , Nobuyuki Kemoto , Toshiya Urabe
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.462-465ZBMATH
摘要:The authors offer a variant of {\it L. Vietoris}' argument [J. Reine Angew. Math. 186, 1-15 (1944; Zbl 0060.19108)] deriving $$f(x+y)=f(x)f(y)-g(x)g(y),$$ for real valued functions $f,g$ of a real variable from $$f(x-y)=f(x)f(y)+g(x)g(y)$$ and then claims to show that from these ...
作者:J\"urgen Gross , G\"otz Trenkler
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.465-468ZBMATH
摘要:Summary: In this note it is shown that the usual restricted least squares estimator is uniquely determined by two of its properties, namely, (a) it is a projection of the ordinary least squares estimator into the linear manifold generated by the restrictions, and, (b) it has smal...
作者:A.F. Gilman
来源:[J].Int. J. Math. Educ. Sci. Technol., 1997, Vol.28 (3), pp.468-472ZBMATH
摘要:$x^3+y^3+z^3- 3xyz$ factors as $[(x^2+y^2+z^2)- (xy+xz+yz)] (x+y+z)$. The author takes $m=y-x$, $n=z-y$ and gets $x+y+z= 3x+2m+n$, and the first factor equals $m^2+mn+n^2$. So it is easy to get a solution for $x$ in parameters $m$, $n$ and a power of the prime $p$. The real quest...

我们正在为您处理中,这可能需要一些时间,请稍等。

资源合作:cnki.scholar@cnki.net, +86-10-82896619   意见反馈:scholar@cnki.net

×