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Lucianpausan20
a fost răspuns

11.Calculati sumele:

f. 1+4+7+...+301=
g.2+7+12+...+177=
h.3+7+11+...+199=

Va rog frumos!

Răspuns :

Dactyls
1+4+7+...+301=
an=a1 + (n-1)r=301
an=1+3n-3=301
3n=303
n=101
Deci: S101=[(1+301)*101]/2
=151*101=15.251

G.
an=2+5n-5=177
5n=180
n=36
S36=[(2+177)*36]/2=179*18=3.222

H.
an=3+4n-4=199
4n=200
n=50
S50=[(3+199)*50]/2=202*25=5.050

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