Question

PLEASE HELP: FAN/MEDAL?!?!
If f(x) = log3 (x + 1), what is f−1(2)?

Answer 1

\[f(x) = \log _{3} (x + 1)\]

Answer 2

what is \[f ^{-1}(2)\]

Answer 3

I don't know how to do the inverse of the log....

Answer 4

here's a shortcut,
find x from
\(\Large 2= \log_3(x+1)\)

Answer 5

ok...
so
\[2 \div(\log _{3}) -1\]
maybe?

Answer 6

here's how that works,
\(y= \log_3(x+1) \\ x+1 = 3^y \\ x= 3^y-1\)
and so,
\(f^{-1}(x) = 3^x-1\)


do you know the definition of log ?
\(\Large \log_ab=c \implies b=a^c\)

Answer 7

ohh.... ok...
so would it be 1?

Answer 8

\(\Large 2= \log_3(x+1) \\ \large \implies 3^2 = x+1\)
you may want to try to find again from this?

Answer 9

try to find "x" again ***

Answer 10

so
3^2 = x + 1
3^2 = 9
9 = x + 1
8 = x?

Answer 11

YES!
thats your f^-1 (2) also :)

Answer 12

Thank you so so so much! :D

Answer 13

most welcome ^_^