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2+3+4+.....+50=?
Repede pls​


Răspuns :

Răspuns:

Scrii=50×(50+1):2

=50×51:2

=2550:2

=1275

R=1
T1=2 Tn=50
Tn=T1+(n+1)*r
50=2+(n+1)*1
50-2=n+1
48-1=n
N=47
S=(T1+T47)*50:2
=(2+50)*25
52*25=1300
Bafta!