Rezultaul calculului (3+6+9+...+99) : (1+2+3+...+33) este:




VA ROG ESTE URGENTT


Răspuns :

(3+6+9+...+99) : (1+2+3+...+33) =

3×(1+2+3+...+33) : (1+2+3+...+33) =

3

( 3 + 6 + 9 + .......+ 99 ) : ( 1 + 2 + 3 + .......+ 33 ) =

= ( 3 × 1 + 3 × 2 + 3 × 3 + ......+ 3 ×33 ) : ( 1 + 2 + 3 + ........+ 33 )

= 3 × ( 1 + 2 + 3 + ........+ 33 ) : ( 1 + 2 + 3 + ........+ 33 ) =

= 3 × 1 =

= 3

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sau aplic formula sumei lui Gauss:

= 3 × ( 1 + 2 + 3 + .......+ 33 ) : ( 1 + 2 + 3 + ........+ 33 ) =

= 3 x [ 33 × ( 1 + 33 ) / 2 ) : 33 x ( 1 + 33 ) / 2 =

= 3 x ( 33 × 34 / 2 ) : ( 33 × 34 / 2 ) =

= 3 × ( 33 × 17 ) : ( 33 × 17 ) =

= 3 × 1 =

= 3