For a>1, b>1, show that (logab)(logba) = 1.

The variable after the log is the base.

How do I go about showing this?

I already know these:

Logbx = Logax / Logab

(again, the variable after the log is the base, i don't know how to write it properly on this forum)

and, Logtb = 1 / Logbt

(variable after log is base)

How do I approach / solve this problem?