Răspuns :
Pentru suma 1+2+3+...+2013 ai formula:
1+2+3+...+2013=[tex] \frac{2013*2014}{2}[/tex]
si ai
2*[tex] \frac{2013*2014}{2}[/tex]÷2014 = 1
1+2+3+...+2013=[tex] \frac{2013*2014}{2}[/tex]
si ai
2*[tex] \frac{2013*2014}{2}[/tex]÷2014 = 1
2(1+2+3+....+2013):2014=
=2x2013x2014:2:2014=
=2013(2014:2014)=
=2013x1=2013
=2x2013x2014:2:2014=
=2013(2014:2014)=
=2013x1=2013