Question

Fie progresia aritmetică (an)n mai mare sau egal ca 1.,a1=1 si a5=13.Calculați a2008.

Answer 1

Uite rezolvarea.........

Answer 2

[tex] a_{5}=a_{1}+4r \\ 13=1+4r \\ 13-1=4r \\ 12=4r =\ \textgreater \ 4r=12 =\ \textgreater \ r=12:4 =\ \textgreater \ r=3 \\ a_{2008}=a_{1}+2007r \\ a_{2008}=1+2007*3 \\ a_{2008}=1+6021=6022.[/tex]