Răspunsuri

2014-05-04T16:20:04+03:00
Deci ex arata astfel : 1-2+3-4+5-...99-100
 =(1+3+5+7+.....99) - (2+4+6+....+100)
=
 \frac{50}{2} [(2*1)+(50-1)*2] -  \frac{50}{2} [(2*2)+(50-1)*2] 
=25[(2+98) - (4+98)]
=25[100-102]
=25* (-2)
= - 50
Pai cam asa se rezzolva
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