If the game only has 20 levels, explain how to find the value of the series for the coins and the points. Use complete sentences and arrive at final values.

I already did the coins one by myself im having trouble with this part because i am plugging my data into a1–a1(r)^(n) / 1- r. My formula (3-3(3)^(3))/(1-3) for the third level.
Level Points
1 3
2 9
3 27

Question

If the game only has 20 levels, explain how to find the value of the series for the coins and the points. Use complete sentences and arrive at final values. 

I already did the coins one by myself im having trouble with this part because i am plugging my data into a1–a1(r)^(n) / 1- r. My formula (3-3(3)^(3))/(1-3) for the third level.
Level	Points
1	3 
2	9
3	27

anonymous · Answer

but i keep getting 39 instead of 27
@phi

chmvijay · Answer

@Ahunter2222 @cwrw238 @ganeshie8 @djcool31 @e.cociuba @fallonbanks @samigupta8 
can u help him :)

phi · Answer

I posted in the chem section.   But to repeat,  your formula finds the sum of the points 3+9+27= 39

you want the nth value,  which is 3^n

anonymous · Answer

yes level 20 is the n value

anonymous · Answer

im a retard

anonymous · Answer

wait nvm I need to solve for the third level so I can show this formula works

anonymous · Answer

I am not getting 27 when i input 3 as the n value showing that my formula does not work

phi · Answer

First, what are you computing?

if you want to list the number of points you get at level n,  it will be  3^n
that formula says  that at level 3, you will get  3^3 = 27 points

on the other hand, if you want to find the total number of points you get from level 1 to level 3, you get 3+9+27= 39 points

anonymous · Answer

ok now I am a retard so my equation was right all along i just forgot that i was adding them.

phi · Answer

It's impolite to call people names.  But if you get confused, it is helpful to think about how you got confused... what did you forget or mis-read... and try to fix that thinking so next time you know what to do.

anonymous · Answer

Well thank you for the help

anonymous · Answer

wait can you tell me if my restrictions are correct?

phi · Answer

what are the restrictions ?

anonymous · Answer

The restrictions on domain of the coins table would be there cannot be any negative levels. Restrictions on the range would be no odd or negative numbers. For the second table the restrictions for the domain would be only positive integers.

anonymous · Answer

Level	Coins
1	2
2	4
3	6
Level	Points
1	3 
2	9
3	27
these are both of my tables

anonymous · Answer

actually positive integers for both the domain and range on the second

phi · Answer

yes, they sound good.   
Though the range for the coins is positive even numbers, {2,4,6...}
it might be ok to just say positive integers

anonymous · Answer

okay
thanks

phi · Answer

yw