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Cum se rezolva :3+7+11+......199=

Răspuns :


(199-3)/4+1=50 termeni

S= (199+3)*50/2=5050

[tex]S=3+7+11+.....+199 \\ S=(1+2)+(3+4)+(5+6)+...+(99+100) \\ S=1+2+3+4+5+6+.....+99+100 \\ S=\frac{100*(100+1)}{2} \\ S=\frac{100*101}{2} \\ S=\frac{10100}{2} \\ S=5050[/tex]