Question

Which of the following recursive formulas represent the same arithmetic sequence as the explicit formula an=5+(n-1)2?

Answer 1

where r the options?

Answer 2

to find choice
find \[a_n-a_{n-1}\]

Answer 3

(An-1+5)•2
An=an-1•5
An=an-1+5
An=an-1+2

Answer 4

the common difference is 2
each term is obtained from the last by adding 2

Answer 5

which of the options will fit that?

Answer 6

a?

Answer 7

\[a_n=5+2(n-1)\\a_{n-1}=5+2((n-1)-1)=5+2(n-2)\\a_n-a_{n-1}=\left[ 5+2(n-1) \right]-\left[ 5+2(n-2) \right]=\\5-5+2(n-1-(n-2))\\a_n-a_{n-1}=2\]

Answer 8

no not a

Answer 9

Oh! I thinks it's b!

Answer 10

i think you are guessing
the first term is 5 and the second is 7

put an = 7 and an-1 = 5 and see which of the options fit

Answer 11

An-1=5

Answer 12

try option b
An = 7
An-1 * 5 = 5*5 = 27
that does not fit

Answer 13

now try c and d