The exponential function
The exponential function has the form
f(x) = ax, a ∈ℝ, a > 0
The most popular of exponential functions is the one having base the Neper number
f(x) = ex
The logarithmic function is of the form
f(x) = loga x, a ∈ℝ, a > 0, a ≠1
Also for the logarithmic function, the most common base is a = e (natural logarithm) and in this case we write
f(x) = loge x = ln x
Its graph is the reflection of the graph of y = ax about the line y = x.