Inverse function

Dale10101

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Feb 25, 2013
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\[\log (z) = \log (x)\log (y)\]

Since none of the "laws of logs" can draw the arguments of log(x)log(y) into the log of a single argument is there a method for getting an analytic solution for z.

I assume the same answer would apply to log(x)/log(y). Thanks.
 
\[\log (z) = \log (x)\log (y)\]

Since none of the "laws of logs" can draw the arguments of log(x)log(y) into the log of a single argument is there a method for getting an analytic solution for z.

I assume the same answer would apply to log(x)/log(y). Thanks.

log(z) = \(\displaystyle \displaystyle log\left (\left [y\right ]^{log(x)}\right )\)
 
log(z) = \(\displaystyle \displaystyle log\left (\left [y\right ]^{log(x)}\right )\)

\[{\log _b}(z) = {\log _b}(x){\log _b}(y)\]

From: \[{\log _b}{\rm{(}}{{\rm{x}}^a}) = a{\log _b}(x)\]

\[\begin{array}{l}
{\log _b}(z) = {\log _b}({y^{{{\log }_b}(x)}}) = > \\
z = {b^{({y^{{{\log }_b}(x)}})}}
\end{array}\]

Now a second formulation with a different result.

\[\begin{array}{l}
{\log _b}(z) = {\log _b}(x){\log _b}(y) = > \\
z = {b^{{{\log }_b}(x){{\log }_b}(y)}} = > \\
z = {b^{{{\log }_b}{{(x)}^{{{\log }_b}(y)}}}} = > \\
z = {x^{{{\log }_b}(y)}}
\end{array}\]

Are both results correct please? I believe I have verified they are equivalent but if so I have a further question about the laws of exponents that I would like to clear up, otherwise I would like to know what I am doing wrong. Also, are they in simplest form, can't get rid of the log function?

Finally, most textbook problems require simplifying a log expression to the log of a single argument before taking it's inverse ... I am now thinking that is not necessarily so ... true? false?
 
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