How can I plot this Function in MATLAB?

I need help plotting a signal f(x) in matlab. The signal is defined as:

f(x) =

{ (x+1)/2 , if -1 <= x < 1

{ 1 , if 1 <= x < 2

{ 0 , else

I cant figure out how to plot f(x) or f(x+1) Any help would be greatly appreciated.

P.S The range of x is from -4:4

Answer 1

[Wouter]

I would make a function of it:

 function y = custom_function(x)
   % y = custom_function(x)

   y = zeros(size(x)); %make y as big as x and fill it with zeros

   first_situation  = x >= -1 && x < 1;
   second_situation = x >= 1 && x < 2;

   y(first_situation) = (x(first_situation) + 1) / 2;
   y(second_situation) = 1;

   % the remainder of the values was already set to zero

 end

to plot this function you would use:

x = -4:4; % set x from -4 to 4
y = custom_function(x);

plot(x,y)

or to plot x+1

x_2 = (-4:4)+1; % set x from -3 to 5
y_2 = custom_function(x_2);

plot(x_2,y_2)

[jason]

Thanks for your reply. I liked your use of commenting. I had been trying for ages to get the plot to work in a "for" loop. Do you know if this is possible,or if i was in the wrong direction completely.

[Wouter]

you can also do it in a for loop:

 x = -4:4            % set x
 y = zeros(size(x)); % make empty y 

 for i = 1:length(x)  % loop through x, index i
   if (x(i) >= -1) && (x(i) < 1)
     y(i) = (x(i) + 1) / 2; % set y at position i 
   elseif (x(i) >= 1) && (x(i) < 2)
     y(i) = 1; % set y at position i to 1
   else
     y(i) = 0; % not really required; y was already 0
   end
 end

 plot(x,y,'r-') % plot x,y as red 'r' line '-'