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S=2+4+6+...+400+402 VA ROG AJUTOR!!!

Răspuns :

Suma lui Gauss

S=[(2+402)102]:2=(404*102):2=202*102=20604

Numarul de termeni daca nu sunt consecutivi: (402-2):2+1=101+1=102
[tex]\displaystyle 2+4+6+...+400+402=2(1+2+3+...+201)= \\ \\ =2 \times \frac{201(201+1)}{2} =2 \times \frac{201 \times 202}{2} =\not2 \times \frac{40602}{\not2} =40602[/tex]