Question

Va rog dau coroana pentru cel mai corect si intreg raspuns!

Answer 1

Ai in poza tot, unde nu înțelegi mă întrebi.

Answer 2

$\displaystyle 29.~~a_3=5,~a_2=6,~a_{2018}=?\\\\ a_n=a_1+(n-1)\cdot r\\\\ \left \{ {{a_3=5} \atop {a_2=6}} \right. \Rightarrow \left \{ {{a_1+2r=5\Big|\cdot(-1)} \atop {a_1+r=6}} \right. \Rightarrow \left \{ {{-a_1-2r=-5} \atop {a_1+r=6}} \right. \\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/~~~-r=1 \Rightarrow r=-1\\\\ a_1+r=6\Rightarrow a_1-1=6 \Rightarrow a_1=6+1 \Rightarrow a_1=7$

$a_{2018}=a_1+2017r \Rightarrow a_{2018}=7+2017 \cdot (-1) \Rightarrow a_{2018}=7-2017 \Rightarrow \\ \\ \Rightarrow a_{2018}=-2010$