Example: Gamma Functions
1. Use the Γ function to plot the Euler gamma function at different values of x.
The function is analytic everywhere except at 0, -1, -2, ... , etc.
2. Use the Incomplete Γ function to plot the incomplete gamma function at different values of x.
3. Use the lnΓ function to plot the natural log of the Euler gamma function at different values of x.