ACT Tips and Advice Post
Below are some TI-83/84/85 programs that you can enter into your calculator for the ACT Math Section. Like many of you, I use a TI-83 Plus graphing calculator, so my instructions are customized for that calculator, but they should work fine for the TI-84/85 series as well. Remember that the TI-89 is not allowed on the ACT, because of its CAS (computer algebra system) functionality! It’s perfectly OK to use programs on your TI-83/84/85, however, because these calculators lack CAS capability*. ACT Calculator Policy
"Q10: Are there any rules that allowed mathematics-related programs must follow? A: Programs must be written in the language of the calculator. Programs written in a different language, compiled, and loaded onto the calculator are not allowed. In this way, the programs can be examined on the calculator and will use calculator functions. Programs must not be lengthy. The limit is 25 logical lines of code. Programs cannot call another program. Techniques such as compressing code into a data statement are not allowed as a way of getting around this limit. Programs are allowed to change the value of system variables so that results may, for example, be graphed through the normal calculator graphing interface."
Pro tip: to include imaginary (nonreal) results, select "Mode" and change "Real" to "a+bi".