首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
一、填空题(每小题4分,共32分)1方程3y2=24的根为;方程x-x28=0的根为.2方程13x=1-5x2的两根之和是,两根之积是3当t时,分式t2+2t-3|t|-3的值为零4当p时,分式方程xx-3=p2x-3+2会产生增根5应用求根公式计算方程ax2+bx+c=0(a≠0)的二根x1与x2的差的绝对值可得|x1-x2|=.6代数式1999x-1998与1998-1999x的值相等,则x=.7方程(2x-1)2+2(1-2x)-3=0的解为;方程组x+y=11xy=-…  相似文献   

2.
本文给出方程dx/dt=x^n+an-1(t)x^n-1+…+a1(t)+a0(t),(1)n=3时分别正好存在1个闭解,3个闭解,以及至少存在2个闭解的充分条件,并研究了这些闭解的稳定性。当n=4且ai(t)(i=0,1,2,3)为t的p次多项式时,文[1]曾猜想其时闭解重数的上界为max{4,p+3}。本文举例指出,即使p=3,闭解重数的上界也可以大于7。这说明该猜想不成立。  相似文献   

3.
1.引言考虑奇阶非线性泛函微分方程[x(t)-cx(t—()](n)+p(t)f(x(t-σ))=0(1)对方程(1)我们作如下假设(H):(H1)n>1是奇整数,p∈C((t0,∞),(t0,∞));(H2)τ>0,σ>0且0≤c≤1;(H3)f∈C(R,R)是单调增加,xf(x)>0,X≠0且当|x|→∞时有|f(t)|→∞.设δ=max{τ,σ},∈C([T-δ,T],R).方程(1)在[T,∞)上的解是指函数x∈C([T,∞),R),使得x(t)=((t),T-δ≤t≤T,[x(t)-cx…  相似文献   

4.
本文研究非线性薛定鄂方程的初始值和边界值问题 iu_t=u_(xx)-g|u|~(p-1)u。0<x,t<∞,这里 g> 0, p> 3; u(x,0)= h(x).假设 h(x)∈ H(IR~+), Q(t),R(t) E C(IR~+).对于二类不同的边界值(狄里克莱型u(0,t)=Q(t)和鲁宾型u_x(0,t)+au(0,t)=R(t);这里a是实数)本文证明古典解。 u∈ C~1(L~2)∩ L~2(H~2)的存在性,唯一性和全局性.  相似文献   

5.
本文讨论了一类具p-Laplacian算子型奇异边值问题(φp(x'))'+a(t)f(x(t))=0,x(0)-βx(0′)= 0,x(1)+ δx′(1)=0多重正解的存在性,其中φp(x)=|x|p-2x,p>1 通过使用不动点指数定理, 在适当的条件下,建立了这类边值问题存在多重正解的充分条件.这些结果能被用来研究椭圆边值问 题多重径向对称解的存在性.  相似文献   

6.
一个反应扩散过程的门槛结果   总被引:3,自引:0,他引:3  
王明新 《数学学报》1994,37(6):735-743
本文讨论反应扩散方程Cauchy问题(ut-△u=u^p-u^p-u,X∈R^n,t∈(0,T),u(x,0)=u0(x)≥0,X∈R^n,解的整体存在性,渐近性质和Blow-up问题,其中1<q<p<n+2/n-2,n≥3或者1<q<p+∞,n=2.得到门槛结果。  相似文献   

7.
一类拟线性二阶微分方程解的振动与非振动的判定   总被引:4,自引:0,他引:4  
杨小京 《数学学报》2001,44(2):311-318
本文讨论了拟线性微分方程(p(x'))'+q(t)p(x)=0,t≥t0,q(t)≥0(这里 p(u)=|u|p-1u,p>0是常数)的解的振动与非振动条件,并改进了文献[2]的结果.  相似文献   

8.
具有非线性边界条件半线性热方程的临界指数林支桂谢春红(南京大学数学系)王明新(东南大学应用数学系)考虑具有非线性边界条件-ux1=uq对x1=0,t∈(0,T)半线性热方程ut-Δu=up在RN+×(0,T)解的爆破性质.证明了若max(p,q)...  相似文献   

9.
该文讨论二维无界带形区域中Navier-Stokes方程(Ⅰ){ut-△u+uiэuэxi=-△p+f(x,t)∈Ω×R+(1)divu=0(2)u(X,t)∈(H^10(Ω)for t〉0(3)u(x,0)=u0(x)∈H(4)其中Ω=(0,d)×R,d〉0为一常数,u与p为未知量,其中u=(u1,u2)为速度场,p表示压力。我们证明了当u0∈H,f∈V且f「log(e+│x│^2)」^12∈L  相似文献   

10.
一类非线性积分偏微分方程的初值问题   总被引:4,自引:0,他引:4  
讨论初值问题ut-auxxt-p(ux)x-∫t0λ(t-s)q(ux)xds=f(x,t)(-∞<x<+∞)t>0,u|t=0=φ(x),ut|t=0=ψ(x)(-∞<x<+∞){整体经典解的存在性·该问题来源于粘弹性力学·在关于已知函数的一些正则性假设和p′(s)≥c1>0,|q′(s)|≤const,λ(0)<0,λ′(0)<λ2(0)的条件下,通过能量估计,证明了该问题整体经典解的存在性·  相似文献   

11.
<正>Submission Authors must use LaTeX for typewriting,and visit our website www.actamath.com to submit your paper.Our address is Editorial Office of Acta Mathematica Sinica,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,P.R.China.  相似文献   

12.
正August 10-14,2015Beijin,China The International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists  相似文献   

13.
14.
The present paper investigates the fractal structure of fractional integrals of Weierstrass functions. The ezact box dimension for such functions many important cases is established. We need to point out that, although the result itself achieved in the present paper is interesting, the new technique and method should be emphasized. These novel ideas might be useful to establish the box dimension or Hausdorff dimension (especially for the lower bounds) for more general groups of functions.  相似文献   

15.
English Series     
正1 Aims and Scope Acta Mathematicae Applicatae Sinica(English Series)is a quarterly journal established by the Chinese Mathematical Society.The journal publishes high quality research papers from all branches of applied mathematics,particularly welcomes those from partial differential equations,computational mathematics,applied probability,mathematical finance,statistics,dynamical systems,optimization and management science.  相似文献   

16.
17.
We characterize congruence lattices of standard QBCC-algebras and their connection with the congruence lattices of congruence kernels. Work on the paper was supported by Council of Czech Government No J14/98:153100011.  相似文献   

18.
A new class of sets in ideal topological spaces is introduced and using these sets, a decomposition of continuity is given.   相似文献   

19.
We obtain (a) necessary and sufficient conditions and (b) sufficient conditions for a compact (countably compact) set to be closed in products (sequential products) and subspaces (sequential subspaces) of normal spaces. As a consequence of these, sufficient conditions are obtained for (i) the closedness of arbitrary (countable) union of closed sets and (ii) the equality of the union of the closures and the closure of the union of arbitrary (countable) families of sets in these spaces. It is also shown that these results do not hold for quotients of even T 4,-spaces.  相似文献   

20.
The current paper considers the problem of recovering a function using a limited number of its Fourier coefficients. Specifically, a method based on Bernoulli-like polynomials suggested and developed by Krylov, Lanczos, Gottlieb and Eckhoff is examined. Asymptotic behavior of approximate calculation of the so-called "jumps" is studied and asymptotic L2 constants of the rate of convergence of the method are computed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号