Question

Determine o decimo segundo termo da PA (4,6,8...)

Answer 1

$PA~\{4, 6, 8, ...\}\\ a_1=4 \\ r=8-6=2\\ n=12 \\ a_{12}=?\\ a_n=a_1+(n-1)\times r\\\\a_{12}=4+(12-1)\times 2 \to\\ a_{12}=4+11\times 2 \to\\ a_{12}=4+22 \to\\ \boxed{a_{12}=26} \\\\\\ PA~\{4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26\}$