# Thread: solve the logarithmic identity:

2. ## Re: solve the logarithmic identity:

What have you tried?
It can be useful to use the definition of a logarithm, for example:
If $x=a^{(1-\log_a(z))^{-1}}$ and you have to evaluate:
$\log_a(x)$
Substitute the given in the equation and so you get:
$\log_a\left(a^{(1-\log_a(z))^{-1}}\right)=(1-\log_a(z))^{-1}$

Try to reform and substitute ...

3. ## Re: solve the logarithmic identity:

Originally Posted by Siron
What have you tried?
It can be useful to use the definition of a logarithm, for example:
If $x=a^{(1-\log_a(z))^{-1}}$ and you have to evaluate:
$\log_a(x)$
Substitute the given in the equation and so you get:
$\log_a\left(a^{(1-\log_a(z))^{-1}}\right)=(1-\log_a(z))^{-1}$

Try to reform and substitute ...
yup i tried but it is hard for me... almost an hour ago,,, can you help me.... to evaluate such that things...