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Mathematics 8 Online
OpenStudy (3psilon):

I am terrible with Logs plz help

OpenStudy (3psilon):

\[f(x) = \log_{3}(\sqrt(x) + 3 \ \]

OpenStudy (3psilon):

Log base 3 square root x plus 3

OpenStudy (3psilon):

How do you find the inverse of this/

OpenStudy (anonymous):

start with the fact that \(\log_3(\sqrt{x})=\frac{1}{2}\log_3(x)\)

OpenStudy (anonymous):

is it the log of the whole thing?

OpenStudy (3psilon):

No just log base 3 square root x

OpenStudy (anonymous):

i mean is it \[f(x)=\log_3(\sqrt{x}+3)\] or \[f(x)=\log_3(\sqrt{x})+3\]

OpenStudy (3psilon):

2nd one

OpenStudy (anonymous):

ok then start with \[f(x)=\frac{1}{2}\log_3(x)+3\]

OpenStudy (anonymous):

we can do the usual trick of writing \[y=\frac{1}{2}\log_3(x)+3\]then \[x=\frac{1}{2}\log_3(y)+3\] and solve for \(y\)

OpenStudy (anonymous):

you need the steps?

OpenStudy (3psilon):

Yes please . I always get confused when there's stuff like log base 3

OpenStudy (anonymous):

1) subtract 3 2) multiply by 2 3) raise 3 to everything

OpenStudy (anonymous):

\[x=\frac{1}{2}\log_3(y)+3\] \[x-3=\frac{1}{2}\log_3(y)\] \[2x-6=\log_3(y)\] \[3^{2x-6}=y\]

OpenStudy (anonymous):

last step because \[\log_b(y)=x\iff b^x=y\]

OpenStudy (3psilon):

Ohhh!!! Thank you so much !

OpenStudy (anonymous):

yw

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