Cum fac 28 b? Nu stiu sa fac nebuniile astea

Răspuns:
Explicație pas cu pas:
Notam paranteza din dreapta cu P
1/2 +2/3 +3/4 +...+2002/2003 =
1-1/2 + 1-1/3 + 1-1/4 +...+ 1-1/2003 =
1+1+1...+1 -(1/2 +1/3 +1/4 +...+1/2003) = 2002 - P
(2002 -(2002 -P)):P = P:P = 1
Răspuns:
1
Explicație pas cu pas:
[tex] \frac{1}{2} + \frac{2}{3} + \frac{3}{4} + ... + \frac{2002}{2003} = (1 - \frac{1}{2} + (1 - \frac{1}{3}) + (1 - \frac{1}{4} ) + ... + (1 - \frac{1}{2003} ) = (1 + 1 + 1 + ... + 1) - ( \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003} ) = 2002 - ( \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003} )[/tex]
deci:
[tex] \frac{2002 - 2002 + ( \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003} )}{\frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003} } = \frac{\frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003}}{\frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}{2003} } = 1[/tex]