a) an=n^k(√n^2 +n+1-√n^2 -n-1), k apartine R
b) an=n^k(√n^2 +1-√n+1)(√n^4 +1 – n)
2) Sa se calculeze limitele sirurilor cu termenul general:
b) an=1*4+2*5+3*6+…+n(n+3)/1^2 +2^2 +3^2+…+n^2
d) an=(√ln1+√ln2+…+√lnn)/n^2
e) an=1/n(1+ 1/2 +1/3 +…+1/n)
f) an=1/n(1/1+√2 +1/√2+√3 +…+1/√n+√n+1)
1a)lim(n->infinit)[n^k(sqrt(n^2+n+1)-sqrt(n^2-n-1))=lim(n->infinit)[n^k.lim(
n->infinit)[((n^2+n+1)-(n^2-n-1))/(sqrt(n^2+n+1)+sqrt(n^2-n-1))]=lim(n->infinit)[n^k.lim(n->infinit)[2(n+1)/(sqrt(n^2).(sqrt(1+0+0)+sqrt(1-0-0))]]=
……..l 0 pentru k<0
n^k=l 1pentru k=0
……..l+infinit pentru K>0
2lim(n->infinit)[n^klim(n->infinit)[(sqrt(n^2+1)-sqrt(n+1)).((sqrt(n^4+1)-n)]=lim(n->infinit)[n^klim(n^3(srt(1+0)-0)(sqrt(1+0)-))]]=lim(n->infinit)
…………..l=0 pentru k<0
[n^k.n^3 l=1 pentru k=0
………….l=+infinit pentru k>0
@DD:
2b)AplicamStolt -Cezaro si L=lim(n->infinit)[ (1.4+2.5+3.6++….+n(n+3)+(n+1)(n+4))-(1.4+2.5+3.6+……n(n+3))]/[(1^2+2^2+3^2+….+n^2+(n+1)^2)-(1^2+2^2+3^2+…..+n^2)]=lim(n->infinit)[(n+1)(n+4)/((n+1)^2)=>1
d)lim(n->infinit)[(suma(k de la 1 la n)[sqrt(ln(k)])/n^2]=lim(n->nfinit)[(suma(kde la 1 la (n+1)[sqrt(lnk)]-suma(k de la 1 la n)[sqrt(lnk)])/[(n+1)^2-
n^2)]=lim(n->infinit)[(sqrt(ln(n+1))/(2n+1)=>0
e)Limita data L<1/n->0
flimita data L<1/(n/(1+sqrt(2)))->0
1a)lim(n->infinit)[n^{k.(((n^2+n+1)-(n^2-n-1))/(sqrt(n^2+n+1)+sqrt(n^2-n-1))]=lim(n->infinit)n^(k.2(n+1)/(n(sqrt(1+0+0)+sqrt(1-0-0)))=lim(n->infinit)[
…………..l0 pentru k<0
n^(k.1)]=l1 pentru k=0
…………..l+infinit pentruk>O
2)lim(n->infinit)[n^{k.n^3((sqrt(1+0)-sqrt(0+0))((sqrt(1+0)-0))=lim(n->
…………………………..l0 pentru k<0
>inFINIT)[n^(k.n^3)=l 1 pentru k=0
…………………………..l+infinit pentru k>o
3)lim(an)=[(1.4+2.5+3.6+…..+n(n+3)+(n+1)(n+4))-(1.4+2.5+3.6+…+n(n+3))]/[(1^2+2^2+3^2+……+n^2+(n+1)^2)-(1^2+2^2+3^2+……+n^2)]=(n+1)(n+4)/(n+1)^2=1
4)lim(an)=[(sqrt(ln1)+sqrt(ln2)+….+sqrt(lnn)+sqrt(ln(n+1))-(sqrt(ln1+sqrt(ln2)+…+sqrt(lnn))]/[(n+1)^2-n^2)]=(sqrt(ln(n+1)))/(2n+1)=0
5)lim(an)=(c+lnn)/n=(c+ln(n+1)-c-lnn)/(n+1-n)=ln((n+1/n)->0
(exista sirul; an=lim(1+1/2+1/3+…+1/n-lnn)=c-constanta lui Euler=0,577)
6)lim(an)=(1/n)(sqrt(2)-1+sqrt(3)-sqrt(2)+…..+sqrt(n+1)-sqrt(n))=(sqrt(n+1)-1)/n->0 (am tinut seama ca 1/(sqrt(k+1)+sqrt(K))=sqrt(k+1)-
sqrt(k))
Ce inseamna? Poti explica mai bine?😕
lim(n->infinit)[
…………..l0 pentru k<0
n^(k.1)]=l1 pentru k=0
…………..l+infinit pentruk>O
pentru k<0 fie k=-2 atunci n^k=n^(-2)=1/n^2-.>0
pentru k=0 atunci n^0=1 (rice numar la puterea 0 este1
pentru k>0 fie k=2 atunci n^2=>+infinit ,clar?