Culegere de probleme de Analiz˘a numeric˘a
Culegere de probleme de Analiz˘a numeric˘a
Culegere de probleme de Analiz˘a numeric˘a
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Problema 5.0.17 Să se calculeze∆ m h 1<br />
x 2 .<br />
un<strong>de</strong><br />
Solut¸ie.<br />
∆ m h<br />
<br />
1 1 1<br />
= +<br />
x2 x x+h +···+<br />
= (−1) m m! u′ m (x)<br />
u 2 m (x)hm<br />
um(x) =<br />
m<br />
(x+kh).<br />
k=0<br />
<br />
1<br />
∆<br />
x+mh<br />
m h<br />
Problema 5.0.18 Să se <strong>de</strong>monstreze<br />
<br />
a0,a1,...,am; 1<br />
<br />
=<br />
t<br />
(−1)m<br />
a0a1...am<br />
Solut¸ie. (prin induct¸ie sau ca s¸i cât <strong>de</strong> doi <strong>de</strong>terminant¸i).<br />
1<br />
x =<br />
Problema 5.0.19 Se consi<strong>de</strong>ră p + 1 puncte distincte a0,a1,...,ap. Să se <strong>de</strong>monstreze<br />
formula<br />
[a0,a1,...,ap;t p ] = <br />
r0+r1+···+rp=n−p<br />
Problema 5.0.20 Să se <strong>de</strong>monstreze formula<br />
a r0<br />
0 ar1<br />
1 ...arp<br />
p .<br />
[a0,a1,...,ak−1,ak+1,...,am;f] = ak −a0<br />
[a0,a1,...,am−1;f]+ am −an<br />
[a1,a2,...,am;f]<br />
Solut¸ie.<br />
am −a0<br />
ak,a0,...,ak−1,ak+1,...,am−1,am<br />
am −a0<br />
[a0,a1,...,am;f] = [a0,...,ak−1,ak+1,...,am;f]−[a0,...,an−1;f]<br />
, (5.1)<br />
am −ak<br />
[a0,a1,...,am;f] = [a0,...,ak−1,ak+1,...,am;f]−[a1,...,am;f]<br />
a0 −ak<br />
Egalând cele două relat¸ii rezultă relat¸ia dorită.<br />
73<br />
(5.2)