Question

calculati folosind factorul comun
1) 4+8+12+...+2012
2) 3+6+9+...+2013
3) 7+14+21+...+2016
4) 5+10+15+...+2015

Answer 1

Răspuns:

a)4+8+12+...+2012

=4(1+2+3+...+503)=507024

b)7+14+21+...+2016=

=7(1+2+3+...+288)=291312

c)3+6+9+...+2013=

=3(1+2+3+...+671)=676368

d)5+10+15+...2015=

=5(1+2+3+...+403)=814060

Am folosit formula lui Gauss

findca prin factorul comun nare cum sal  faci

Answer 2

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