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Rapoarte

Posted: Sat Nov 08, 2008 5:19 pm
by alex2008
Fie rapoartele : \( \frac{x_1}{y_1}=1 \) ; \( \frac{x_2}{y_2}=2 \) ; \( \frac{x_3}{y_3}=3 \) ; ... \( \frac{x_n}{y_n}=n \) , n este natural diferit de zero . Calculati :
a)\( \frac{x_1+x_2+x_3+...+x_n}{y_1+2y_2+3y_3+...+ny_n} \) b)\( \frac{nx_1x_2x_3...x_n}{y_1y_2x_3...x_n+x_1y_2y_3x_4...x_n+...+x_1x_2...x_{n-2}y_{n-1}y_n} \)