# Math Help - derive function for logarithm chat

1. ## derive function for logarithm chat

Anyone knows how to derive a function for this chat?

y=f(x)=???

2. Originally Posted by trip2898

Anyone knows how to derive a function for this chat?

y=f(x)=???

This is of the general form:

$y=m \log(x) + c$

To find $m$ and $c$ from the graph it is probably best to use logarithms to the base $10$, so:

$y=m \log_{10}(x) + c$

Now you can put $u=\log_{10}(x)$, and relabel the horizontal axis with the corresponding values of $u$, and you will have a standard straight line plot:

$y=m u +c$

CB