Thread: Log equation that matches graph?

1. Log equation that matches graph?

Which equation matches the graph? It could be one of each of the options, none of them or 1 and 3. I thought it was all of them? But I guess it can't be. Is it just 1 and 3? Why wouldn't number 2 work?

2. Re: Log equation that matches graph?

Originally Posted by canyouhelp
Which equation matches the graph? It could be one of each of the options, none of them or 1 and 3. I thought it was all of them? But I guess it can't be. Is it just 1 and 3? Why wouldn't number 2 work?
Here is a hint. $\log_b(T)$ is defined only if $T>0$. There is just one of those options that works.

3. Re: Log equation that matches graph?

Originally Posted by Plato
Here is a hint. $\log_b(T)$ is defined only if $T>0$. There is just one of those options that works.
Thanks! Would this be option II then? Because the first one a has to be less than 0, and the third turns T negative, right?

No.