Question

Va rog frumos !! Repede !! Dau coroana la primul care raspunde !
Calculeaza folosind proprietatile adunarii : S= (1 supra 2 + 1 supra 3 + 1 supra 4 + 1 supra 5 + 1 supra 6 ) + (1 supra 2 + 2 supra 3 + 3 supra 4 + 4 supra 5 + 5 supra 6 )

Answer 1

S= (1 supra 2 + 1 supra 3 + 1 supra 4 + 1 supra 5 + 1 supra 6 ) + (1 supra 2 + 2 supra 3 + 3 supra 4 + 4 supra 5 + 5 supra 6 )

S= (1/2 + 1/3 + 1/4 + 1/5 + 1/6 ) + (1/2 + 2/3 + 3/4 + 4/5 + 5/6 )


[tex]\it S= \left(\dfrac{1}{2} +\dfrac{1}{3} +\dfrac{1}{4} +\dfrac{1}{5} +\dfrac{1}{6} \right) + \left(\dfrac{1}{2} +\dfrac{2}{3} +\dfrac{3}{4} +\dfrac{4}{5} +\dfrac{5}{6} \right) = \\\;\\ \\\;\\ = \left(\dfrac{1}{2} +\dfrac{1}{2} \right) + \left(\dfrac{1}{3} +\dfrac{2}{3} \right) +\left(\dfrac{1}{4} +\dfrac{3}{4} \right) +\left(\dfrac{1}{5} +\dfrac{4}{5} \right)+\left(\dfrac{1}{6} +\dfrac{5}{6} \right) = \\\;\\ \\\;\\ = 1+1+1+1+1=5 [/tex]