In the Lab we developed a two programs. One called gendata.py which asked the user for a filename and a math function and output points along that function to a data file. Then we worked on second program called differ.py (short for "differentiate") which would read in the points from the data file, plot the function, and estimate its derivative by computing the slope of the line connecting one point to the next. The assignment is to modify this program to try to compute a more accurate estimate of the derivative at each point by computing the slope the line connecting the points immediately ahead and behind.