#### Answer

$a_1=1$
$a_2=1$
$a_3=2$
$a_4=3$

#### Work Step by Step

$a_1=1$
$a_2=1$
$a_3=a_1+a_2=1+1=2$
$a_4=a_2+a_3=1+2=3$

Published by
Pearson

ISBN 10:
013421742X

ISBN 13:
978-0-13421-742-0

$a_1=1$
$a_2=1$
$a_3=2$
$a_4=3$

$a_1=1$
$a_2=1$
$a_3=a_1+a_2=1+1=2$
$a_4=a_2+a_3=1+2=3$

You can help us out by revising, improving and updating this answer.

Update this answerAfter you claim an answer you’ll have **24 hours** to send in a draft. An editor
will review the submission and either publish your submission or provide feedback.