Question

Cho tổng S=1+3+5+.........+2009+2011.Tính S

Answer 1

\(S=1+3+5+...+2009+2011\)

\(S=\dfrac{\left(\dfrac{2011-1}{2}+1\right).\left(2011+1\right)}{2}=1012036\)

Answer 2

S = 1 + 3 + 5 + ... + 2009 + 2011

= [ ( 2011 - 1 ) : 2 + 1 ] . ( 2011 + 1 ) : 2

= 1006 . 2012 : 2

= 2 024 072 : 2

= 1 012 036