Question

Îmi puteți spune cu rezolvare completa va rog frumos!Urgent!!​

Answer 1

Răspuns:

a= 1+5/2+10/3+17/4+...+100/99=

(1+4/2+1/2)+(9/3+1/3)+(16/4+1/4)=

a=(1+2+3+4+....+99)+(1/2+1/3+1/4+...+1/99)

b=1/2+2/3+.+98/99=(2-1)/2+(3-1)/3+.+(99-1)/99

1-1/2+1-1/3+1-1/4+..+1-1/99=

b=98-(1/2+1/3+1/4+...+1/99)

a+b=(1+2+3+...99)+(1/2+1/3+.. 1/99)-

98-(1/2+1/3+.. +1/99)=

1+2+3+4+...+99+98=99×100/2+98=

4950+98=5048

suma= n(n+1)/2