Example: Error Functions
1. Use the erf function to plot the Error function at different values of x.
Function erf is symmetric about the y=0 line.
2. Use the erfc function to plot the Complementary Error function at different values of x.
Functions erfc is symmetric about line y=1.0.
3. Create a plot to show the relationship between the erf and erfc functions at different values of x.
The functions are symmetric around the y=0.5 line.
4. Create a plot to show that erfc(x)=1-erf(x) at different values of x.
