Question

Найдите сумму: 

1/15 + 1/14х15+1/13х14+1/12х13+1/11х12 

 

 

Answer 1

$frac{14}{14*15} + frac{1}{14*15} = frac{15}{14*15} = frac{1}{14}$
$frac{1}{14} + frac{1}{13*14} = frac{1}{13}$
$frac{1}{13} + frac{1}{12*13}= frac{1}{12}$
$frac{1}{12} + frac{1}{12*11} = frac{1}{11}$