Question

Find the fifth term of the arithmetic sequence in which

Answer 1

We have given $t_{1}=3$ and $t_{n} = t_{n-1} + 4$. Fifth term is $t_{5}= t_{4}+4$. It means we need to find $t_{4}$ and in order to find the latter, we have to find $t_{4}= t_{3}+4$, $t_{3}= t_{2}+4$ and $t_{2}= t_{1}+4$ . Since we know the value of  $t_{1}$, beginning from the last equation we can find the value of  $t_{5}$. We can write that $t_{2}= t_{1}+4=3+4=7$, $t_{3}= t_{2}+4=7+4=11$ and $t_{4}= t_{3}+4=11+4=15$. Since $t_{5}= t_{4}+4$, then $t_{5}= 15+4=19$