Question

am nevoie de ajutor. Rapid!!!!!​

Answer 1

Răspuns:

Explicație pas cu pas:

a)

2 + 4 + 6 + .....+ 200 = 2*(1 + 2 + 3 + ....+ 100)

fractia devine

(1 + 2 + 3 + ....+ 100)/2*(1 + 2 + 3 + ....+ 100) = 1/2

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b)

101 + 102 + 103 + .... + 200

=100 + 1 + 100 + 2 + 100 + 3 + .... + 100 + 100

=100*100 + 1 + 2 + 3 + .... + 100 = 100*100 + 100*(1 + 100)/2 =

= 100*100 + 50*101 = 10000 + 5050 = 15050

fractia devine

5050/15050 = 101/301

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c)

1 + 3 + 5 + .....+ 99 = 50*(1 + 99)/2 = 50*100/2 = 50*50

2 + 4 + 6 + ....+ 100 = 50*(2 + 100)/2 = 50*102/2 = 50*51

fractia devine

50*50/50*51 = 50/51

Answer 2

Este suma lui Gauss
2+4+6+..........+200= 200*(200+1) : 2. = 200*201 : 2
= 40.200 :2
=20.100