discontinuity missing.

Hello

This might seem a really easy question for some of you but I can't fix it.

I need to create a function M-file for the function

f(x) = 1-x if 0<=x<=1  [1]   and

f(x) = -1-x if -1<=x<0   [2]

I've tried to do this with

if (x >= 0) & (x <= 1)     % x is [1]

      y = +1 -x;
  else
      y = -1 -x;  % x is [2] or outside of the domain (y doesn't matter so it can be -1-x

end

However when I try to plot this function it remains just one straight line y=-1-x It is probably something really obvious that I'm missing here but I'm not really experienced with matlab.

[Sean de Wolski]

Well written question; you get a vote!

Answer 1

[Paulo Silva]

Connected lines 

x=-1:0.01:1;
y(x>=-1 & x<0)=-1-x(x>=-1 & x<0);
y(x>=0 & x<=1)=1-x(x>=0 & x<=1);
plot(x,y)

Alternative, not connected lines

x1=-1:0.01:0-0.01;
x2=0:0.01:1;
y1(x1>=-1 & x1<0)=-1-x1(x1>=-1 & x1<0);
y2(x2>=0 & x2<=1)=1-x2(x2>=0 & x2<=1);
plot(x1,y1)
hold on
plot(x2,y2,'r')

[Sean de Wolski]

Good example.