Le forum de XCAS

One way the classes command can be used is to give it a list of numbers, a starting number, and a list of midpoints
and we will get a list of intervals with how many numbers are in each interval. However, the starting number seems to be ignored:

classes([0,0.5,1,1.5,2,2.5,3,3.5,4],1,[1,3,5])

classes([0,0.5,1,1.5,2,2.5,3,3.5,4],0,[1,3,5])

and

classes([0,0.5,1,1.5,2,2.5,3,3.5,4],0.5,[1,3,5])

all return

[[0.0 .. 2.0,4],[2.0 .. 4.0,4],[4.0 .. 6.0,1]]

for example, but if that number is left off,

classes([0,0.5,1,1.5,2,2.5,3,3.5,4],[1,3,5])

returns

[undef]

Does the starting number do anything?

Jay