Maintenance script: Initial automated import

2016-02-24T18:14:48Z

Initial automated import

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{{Template:TI-BASIC:Command
|picture=DELTALIST.GIF
|summary=Calculates the differences between consecutive terms of a list.
|syntax=ΔList(''list'')
|location=Press:
# 2nd LIST to access the list menu.
# RIGHT to access the OPS submenu.
# 7 to select ΔList(, or use arrows.
|compatibility=TI-83/84/+/SE
|size=2 bytes
}}

ΔList( calculates the differences between consecutive terms of a list, and returns them in a new list.

ΔList({0,1,4,9,16,25,36})
{1 3 5 7 9 11}

= Advanced Uses =

The ΔList( command is very nearly the inverse of the [[TI-BASIC:Cumsum|CumSum(]] command, which calculates the cumulative sums of a list. For any list, ΔList(cumSum(''list'')) will return the same list, but without its first element:

ΔList(cumSum({1,2,3,4,5,6,7}))
{2 3 4 5 6 7}

Removing the first element would otherwise be a difficult procedure involving the [[TI-BASIC:Seq_List|seq(]] command, so this is a useful trick to know.

If a list is sorted in ascending order, min(ΔList(''list'')) will return 0 (false) if there are repeating values in the list, and a value corresponding to true if they are all distinct.

= Error Conditions =

* '''[[TI-BASIC:Errors#invaliddim|ERR:INVALID DIM]]''' is thrown if ΔList( is run on a single element list.

= Related Commands =

* [[TI-BASIC:Sum|Sum(]]
* [[TI-BASIC:Cumsum|CumSum(]]
* [[TI-BASIC:Augment|Augment(]][[Category:TI-BASIC]]
[[Category:TIBD]]

TI-BASIC:Deltalist - Revision history

Maintenance script: Initial automated import