Question

Qual é o vigésimo termo na PA (1,4...)​

Answer 1

$a_n=a_1+(n-1)\cdot r$

$a_{20}=1+(20-1)\cdot3$

$a_{20}=1+19\cdot3$

$a_{20}=1+ 57$

$\boxed{\boxed{a_{20}=58 }}$