A video game has been developed whereby the player must earn a certain number of experience points before progressing to the next level.

On level 1, a player must earn 1 experience point.
On level 2, a player must earn 7 experience points.
On level 3, a player must earn 15 experience points.
On level 4, a player must earn 25 experience points.

Which recursive equation represents the pattern?
Multiple Choice:
an = an – 1 + n

an = an – 1 + 3n + 1

an = an – 1 + 5n

an = an – 1 + 2(n + 1)

Question

A video game has been developed whereby the player must earn a certain number of experience points before progressing to the next level. 

On level 1, a player must earn 1 experience point. 
On level 2, a player must earn 7 experience points. 
On level 3, a player must earn 15 experience points. 
On level 4, a player must earn 25 experience points. 

Which recursive equation represents the pattern? 
Multiple Choice:
 an = an – 1 + n

 an = an – 1 + 3n + 1

 an = an – 1 + 5n

 an = an – 1 + 2(n + 1)

anonymous · Answer

i don't know lets check on
how about $ a_n = a_{n – 1} + 2(n + 1)$ and maybe we will get lucky

anonymous · Answer

im not quite sure what to do

anonymous · Answer

$a_1=1$
$a_2=7=^?1+2(2+1)=^?1+6=7$ ok that one works for $a_2$ lets see if it continues to work

anonymous · Answer

okay

anonymous · Answer

$a_3=15=^?7+2(3+1)=^?7+8=15$ ok that one looks good too!

anonymous · Answer

$a_4=25=15+2\times 5=15+10=25$ whew i would have been annoyed if we had to try a different formula
looks like the last one works, just by trying it

anonymous · Answer

Okay thanks can you help me with another one please