Question

f)2+4+6+....+100=
g)1+3+5...+99=
j)7+14+21+.....+2002=​

Answer 1

Răspuns:

Explicație pas cu pas:

2+4+6+....+100 = 2*(1 + 2 + 3 + ....+ 50) = 2*50*51/2 = 50*51 = 2550

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7+14+21+.....+2002 =​ 7*(1 + 2 + 3 + ...+ 286) = 7*286*287/2 = 287287

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1+3+5...+99 = 1 + 2 + 3 + 4 + 5 + ....+ 98 + 99 + 100 - (2 + 4 + 6 + ...+ 100)

= 99*100/2 - 2550 = 4950 - 2550 = 2400