As x approaches -infinity f(x) approaches 0 As x approaches infinity f(x) approaches Infinity ... logarithmic functions have what kind of asymptote? Logarithmic functions are inverses of exponential functions. Let's take a look at the end behavior of our exponential functions. We learned that exponential functions are the functions where our variable is in the exponent, and logarithmic functions are the functions where our variable is the argument of the log function. growth or decay factor, b>1 growth, 0