Question

Cine ma ajuta are 23 puncte.Si COROANA.​

Answer 1

Răspuns:29

prima suma telescopica=1-1/2+1/2-1/3+1/3-1/4+1/4-.......+1/44-1/45

=1-1/45

a doua suma telescopica

=1/45-1/46+1/46-1/47+1/47-1/48+1/48-.......+1/89-1/90

=1/45-1/90

dif celor 2 sume=1-1/45-(1/45-1/90)

1-1/45-1/90

44/45-1/90

88/90-1/90

87/90

radical din 29*30*(87/90)

din 29*30*(29/30)

radical din 29*29=>29