How to solve this logarithm without using the change of base formula?

Question

I'm doing an assignment on logarithms, and I've stumbled upon a tricky question. The task looks like this:

For the first 3 I have no problem. However, for d) I have no idea where to begin. I just can't see any way to solve it without using the change of base formula. Can anyone help?

Do you remember that, whatever could be the base, a log(b) = log(b^a) ? — Claude Leibovici, Dec 08 '13 at 17:35

score 1 · Accepted Answer · edited Apr 13 '17 at 12:20

1

Beyond what is in the comments, that $5\log_5(13)=\log_5(13^5)$, you can't do anything else. It is shown here that $\log_5(13)$ must be irrational.

edited Apr 13 '17 at 12:20

Community

1

answered Dec 08 '13 at 17:51

J126

17,451

How to solve this logarithm without using the change of base formula?

1 Answers1