Question

USE SUMMATION NOTATION TO WRITE THE SUM... pls help!

Answer 1

\[\sum_{n=1}^{??} 10(3)^{n-1}\]

Answer 2

@campbell_st

Answer 3

idk, I thought setting 7290 = 10(3)^n-1 would help but idk...

Answer 4

looks good to me

Answer 5

oh you need the upper limit right?

Answer 6

yes! ^_^

Answer 7

\[7290=10\times 3^{n-1}\] solve for \(n\) via \[279=3^{n-1}\] then just guess

Answer 8

find a power of 3 that gives \(729\)

Answer 9

ohhhhh 9

Answer 10

oops typo there
\[729=3^{n-1}\]

Answer 11

no i don't think so

Answer 12

\(3^8=6561\) too big
try a smaller one

Answer 13

the bases have to be the same right?

Answer 14

you are thinking too hard
use a calculator
\[3^2=9\\
3^3=27\\
3^4=81\\
3^5=...\] keep going until you get it, it will be soon

Answer 15

yeah 3^6

Answer 16

that's why the upper limit is 7

Answer 17

ok so that makes your upper limit 7 i guess

Answer 18

thanks! :)