ti-basic

TI BASIC remainder() domain error


In my TI BASIC program on TI 84 plus C, I have a line that says remainder((A/X),2). This creates a domain error every time the program runs. In the case of my tests, A/X is 4. remainder(4,2) works. 4->Z remainder(Z,2) works. If I pause the program and display (A/X) immediately before the remainder line, the result is certainly 4. (A/X)->Z remainder(Z,2) does not work. What could possibly be wrong with my code?

link to the code:

https://drive.google.com/open?id=0B07yHA0-EssLUjZOc0dxektwbUU

https://drive.google.com/open?id=0B07yHA0-EssLSFlNcFNWZm0zNDQ


Solution

  • Here is a valid substitution for remainder().

    2fPart(A/(2X))
    

    This works because the general form, KfPart(A/K) takes the fractional part of A/K, which will be the same as remainder(A,K) if A is an integer. TI-BASIC doesn't always return an integer value. For example, logBASE(16,2) is ever so slightly less than 4. When we multiply by K, we change the range from being 0 to 1, to 0 to K.

    Nothing is inherently wrong with your code, it is TI-BASIC that is sometimes wrong.