Question

Am nevoie cât mai scurt exercitiul 30

Answer 1

Răspuns:

Explicație pas cu pas:

1/1*2 = 1/1 - 1/2

1/2*3 = 1/2 - 1/3

1/3*4 = 1/3 - 1/4

......

1/42*43 = 1/42 - 1/43

a = 1/1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 +...+ 1/42 - 1/43 = 1/1 - 1/43 = 43/43 - 1/43

= 42/43

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1/2*3 = 1/2 - 1/3

1/3*4 = 1/3 - 1/4

1/4*5 = 1/4 - 1/5

.......

1/125*126 = 1/125 - 1/126

b = 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + ...+ 1/125 - 1/126 = 1/2 - 1/126

= 63/126 - 1/126 = 62/126

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a/b = (42/43)/(62/126) = 42/43*126/62 = 21*126/43*31 = 2646/1333