Express functions more simply using abs()?

Question

I have 2 functions (the BLUE and RED functions defined from 0 to 4) that I think can be expressed more simply using the Math.abs() function. But I can't do it, I hope you can. Here are the functions in javascript:

  plot1(function(x) { // the BLUE function
    if (1<x && x<2) return 2-x;
    if (2<x && x<3) return 6-x;
                    return   x;
  } );   
  plot1(function(x) { // the RED function
    if (x<1) return 2-x;
    if (3<x) return 6-x;
             return   x;
  } );

EDIT1: I have this little improvement for the RED function:

  if (x<3) return 1 + Math.abs(x-1);
  else return 1 + Math.abs(x-5);

What are the coordinates for the graph? Is the lower left corner the origin (0,0)? — gd1035, Jul 03 '18 at 18:25

score 0 · Answer 1 · answered Jul 03 '18 at 18:35

0

I think this would need to be defined piecewise:

If x<1, then blue = Math.abs(x)
Else if x<2, then blue = -1 * Math.abs(2-x)
Else if x<3, then blue = -1 * Math.abs(6-x)
Else blue = Math.abs(x)

Give the red function a try

answered Jul 03 '18 at 18:35

gd1035

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score 0 · Accepted Answer · answered Jul 04 '18 at 00:55

I would like to say that I got these through keen analysis, but I must admit there was a lot of experimenting. This is what I was looking for. The % is the MOD or REMAINDER function in javascript. (Can I accept my own answer?)

  plot1(function(x) { // the RED function
    return 1 + Math.abs((x+1)%4 - 2);
  } );   

  plot1(function(x) { // the BLUE function
    return (3 + Math.abs((x+3)%4 - 2)) % 4;
  } );

Express functions more simply using abs()?

2 Answers2