Take a look at the applet: Logarithm
The solution of the equation is called the logarithm of to base .
Notation: .
Since this equation only has solutions if or and if , can only exist under these conditions.
For the time being you mostly use the intersect function of your graphing calculator
to determine .
The general definition for logarithms is:
from follows ;
from follows ;
The expressions en are completely equivalent if or and if .
The exponential function and the logarithm with the same base are called inverse operations, since they reverse the effect of each other.