Question

An= 2an-1 +5 what is the value of a5 a1 = 1

Answer 1

Answer:

$a_5=91$

Step-by-step explanation:

The general term formula is:

$a_n=2a_{n-1}+5$

And given first term is "1",

The general term formula means, to get a term, multiply the previous term by 2 and sum it with "5".

Lets find a_2:

$a_2=2a_{1}+5\\a_2=2(1)+5\\a_2=7$

Now, finding a_3:

$a_3=2a_2+5\\a_3=2(7)+5\\a_3=19$

Now, a_4:

$a_4=2a_3+5\\a_4=2(19)+5\\a_4=43$

Finally, finding a_5:

$a_5=2a_4+5\\a_5=2(43)+5\\a_5=91$

This is the answer.