SCIENTIFIC ABSTRACT IONESCU, D.V. - IONESCU, FL

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R000518710005-4
• Release Decision: RIF
• Original Classification: S
• Document Page Count: 100
• Document Creation Date: January 3, 2017
• Document Release Date: July 27, 2000
• Sequence Number: 5
• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT

7L

Romtne. Bul., 'Sett- $ti. MaL Fiz- 9 (19S61. 67-100-
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7 :2~a~7 U

IONESCU) D* V.0 prof,
Application of forwalas of numbrical derivation to the nworical
integration of differential equations, Studii car mat 10 no.2s
259-315 159. (EW 3.0t9/10)
1. Univernitates. Babes-Bolyai, Cluj, Catedra do ecuatii diferentials,
membru, al Comitetului do redactio, "Studii si cerestari do matematicall
(Filiala Cluj).
(Differential equations) (Integrals)
(Nmerical functions)

LS66 8/044/62/006/007/052/100
-cl-11/0333
AUTHOR: lonescu, D. V.
TITLE:" (-akm--a~caition "of 's"'u"ccessive approximations. to the numeri-
Cal integration of differential equations
PERIODICALt Referativnyy zhurnalt Matematikat no. 7,-1962, 26,
abstract 7V129. ("Bull. math. Soo*.-sci. math. et phys.
no'.. 4, 423-431)
TEXT: The approximate solution of the equation yl f(x,y) with fD-'
the initial oonditiln y(x 0 0 is determined by the successive
~~approximations
x x
(0)(,
Y Y. d~ (a-lp2
0 ]dj, toy
X
0 0
It is suggested that the value s"oi Y:(B)(x) in the points xjj ... 9x be
calculated using an improved trapezoid formula, thereby using the
obtained values
y (xi The necessary exactness of the approximate solution in the
Card 1 2

S/044/62/000/007/052/100
The application of successive CIII/C333
points x 1 xn with corresponding-s is guaranteed by some-natural.
.assumptions concerning the function f(x,y). An analogous method for
the solution of the hyperbolio equation
-,2
i z f(xpyqzvpyq) (Z(X,O) Z(O,y) 0)
X.)
4z
where p 7 z i a giv on.
q
~Abstracterls notei Complete translation
Card 2/2

IONMU D V . prof - (Glui)
The cubeture fo=ulas; application in the numerical integration of
the equations vith partial derivatives of the second order of a byper-
bolie type. Studii care mat Gluj 11 no.1;35-78 '60.
(=I 1019)
1. Gomitetul do rodactio wStudii si cereetari do matematical.
(Equationsi (Integmls) (Hyperbola)

44366
S/044/62,/000/012/031/049
AOW/AOOO
AUTHOR: Ionescu, D.V.
TITIS: Application of the method of successive approximations to the nume-_
rical inte"gration of differential equations
F~MIODICAL: Reforativngy zhurnal, Matematika, no. 12, 1962, 29 - 30, abstract
12V156 (Stddii oi cercet9ri mat. Acad. RPR Fil. Cluj, 1960, v. 11,
no. 2, 273 286; Rumanian; summirtries in Russian, Prench)
A numerical realization is constructed for the known method of Pl- A
TqT
caikdl ssuccessive approximations for the solution of the Cauchy problem
Y' - f (x" Y), Y (X0) ..j0
consisting in that the segment xO 4 x 4 X0 + of the x line is covered by a
grid r with points xO, xj, Xn xO + and at the J-th step of the process
X
(x) f d?., v- 1. 2, (2)
XO
Card 1/3

S/044/62,/000/012/031/049
Application of the method of subobasive .... A060/AOOO
one defines the quantities y 1, n and the integrals
Xi
f (g)) dt
XO
are calculated by the quadrature formula
2
(x) dx + 4) + R (3)
2 12
OL
R (x OL) 2 x)2 IV (x) dx
24
The following theorem is proven: Letz- 1) the function f (x, y) be defined on'
the rectangle D(xO