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Cum il aflu pe a????


Cum Il Aflu Pe A class=

Răspuns :

2/(1*3)=1-1/3

4/3*7=(1/3-1/7)

5/7*12=1/7-1/12

7/12*19=1/12-1/19

atunci a=1-1/3+1/3-1/7+1/7-1/12+1/12-1/19=1-1/19=18/19

1/3<18/19<19/20 ?
1/3<18/19?
1/3<7/21<7/19<18/19 da ,este adevarat
deci 1/3<18/19

18/19<19/20??

18*20/(19*20)<19*19/(19*20) ?

18*20<19*19?
360<361? da ,este adevarat
deci 18/19<19/20