The R functions below can be used : geom_hline()for horizontal lines geom_abline()for regression lines geom_vline()for vertical lines geom_segment()to add segments Related Book: GGPlot2 Essentials for Great Data Visualization in R geom_hline : Add horizontal lines ...
[ggplot](https://pypi.python.org/pypi/ggplot) ## 4. Linear Algebra [Linear Algebra, from UC Davis](https://www.math.ucdavis.edu/~linear/) [Linear Algebra, from Saint Michael's College](http://joshua.smcvt.edu/linearalgebra/) [Linear Algebra Done Wrong](http://www.math.brown.edu/...