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1/1*3+1/3×5+1/5×7.......+1/99×101 <1/2

Răspuns :

1/2 [ 1-1/3 +1/3-1/5+15-1/7 +......1/899-1/100]=
1/2 (1-1/100) =[1/2]* [(100-1)/100 ]=(1/2)*(99/100)<1/2, cerinta

am tinut cont ca
1/3= 1/2 ( 1-1/3)=(1/2) * (3-1)/3
 si
1/(3*5) = 1/2 * ( 1/3-1/5)= 1/2* (5-3)/(3*5)
etc