Question

media aritmetica a nr: a= 1/2+ 1/3+1/4+....+1/2012 si b=1/2+2/3+3/4+4/5+....+2011/2012

Answer 1

$m_a= \frac{a+b}{2}= \frac{ \frac{1}{2}+\frac{1}{3}+...+\frac{1}{2012}+\frac{1}{2}+\frac{2}{3}+...+\frac{2011}{2012} }{2}=\frac{(\frac{1}{2}+\frac{1}{2})+(\frac{1}{3}+\frac{2}{3})+...+(\frac{1}{2012}+\frac{2011}{2012})}{2} \\ m_a=\frac{1+1+1+...+1}{2}=\frac{2011}{2}$

Answer 2

Ma=(a+b)/2
a+b=1/2+1/3+1/4+...+1/2012+1/2+2/3+3/4+...+2011/2012
grupezi 1/2 +1/2=1
1/3+2/3=1
........
1/2012+2011/2012=1
aduni totul si obtii  1 de 2012 ori
inlocuiesti in Ma=2012/2=1006