Question

11+12+13+...+78;
5+8+11+...+305;
e suma lui Gauss

Answer 1

Răspuns:

S=11+12+13+...+78

S=78+77+76+...+11

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2*S=89+89+89+...+89

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(78-11):1+1=67+1=68 termeni

2*S=89*68

S=6052:2=3026

S=5+8+11+...+305

S=305+302+...+5

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2*S=310+310+....+310

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(305-5):3+1=101 termeni

2*S=310*101

S=31310:2=15655