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1+3+5+7+...+2005=?     
2+4+6+...+2006=?  
Cum aflu rezultatele?vreau rezolvarea si formulele...

Răspuns :

Miky93ask
1+3+5+...+2005=

n=(2005-1):2+1
n=2004:2+1
n=1002+1
n=1003 -termeni

1+3+5+....+2005=(1+2005)*1003/2=  2006*1003/2=  1003*1003=1003²

2+4+6+...+2006=2(1+2+3+....+1003)=2(1+1003)*1003/2=  1004*1003=1007012


AddaPiticask
2+4+6+....+2006= 2(1+2+3+....+1003)= 2(1003*1004) / 2= 1003*1004
1+3+5+....+2005=1+ (1+2)+ (1+4)+ ...+ (1+2004)= (1+1+1+...+1) +2( 1+2+3+4+...+ 1002)= 1003+ 1002*1003= 1003(1+1002)= 1003*1003

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