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a=2+4+6+8+...+2026+2028• •[(1/2013•2014) - (1/2014•2015)]
Dau coroana!


Răspuns :

a=2+4+6+8+...+4026+4028• •[(1/2013•2014) - (1/2014•2015)]

a = 2 ×(1+2+3+4+...+2013 + 2014) ×
[(1/2013•2014) - (1/2014•2015)]

a = 2 × 2014 × 2015 : 2 × (2015 - 2013)/2013×2014×2015

a = 2014 × 2015 × 2/2013×2014×2015
(se simplifica 2014 × 2015)

a = 2/2013