Răspunsuri

2014-10-02T20:41:37+03:00
Faci contor :
 1+3+5+.......+199
  1=2X0+1
  3=2X1+1 -apare singur de 100 ori
  5=2X2+1
...............
199=2X99+1
  S=2(0+1+2+3+........+99)+100X1
S=2(99X100:2)+100
S=99X100 +100
S=100(99+1)
S=100X100
S=10000
 
41 4 41
2014-10-02T20:44:02+03:00
1+3+5+...+2n-1=n*n 
199=2n-1 de unde 2n=199+1=200 
n=200
Deci suma S=n*n =200*200=40000
41 3 41