Animating sin(x-a): Tracking a Changing Title

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THIS WAS RESOLVED

Homework Statement

In a problem I had to create a animation of the function
sin(x-a)
were a ranged from 0 to 8pi

x=[-2*pi:.00001*pi:2*pi];
a=0;
y=sin(x-a);
g=plot(x,y);
grid on;
title('sin(x-0)')
set(g,'EraseMode','xor')
while a<=8*pi
    a=a+.1*pi;
    y=sin(x-a);
    set(g,'ydata',y)
    drawnow
end

My code worked fine and did what it was suppose to do. I however was trying to get MATLAB to change the value of a in the title each time it went through the loop and I seem to be having difficulties doing this.

Homework Equations

The Attempt at a Solution

Here's my attempt at what I thought would produce what I was looking for.

x=[-2*pi:.00001*pi:2*pi];
a=0;
y=sin(x-a);
g=plot(x,y);
grid on;
title('sin(x-a)')
set(g,'EraseMode','xor')
while a<=8*pi
    a=a+.1*pi;
    y=sin(x-a);
    set(g,'ydata',y)
    drawnow
    title(fprintf('sin(x-%s)\n',num2str(a)));
end

I thought this would work. Before it enters the loop the title would get defined as sin(x-0). I thought that it would then redefine the title in this line
title(fprintf('sin(x-%f)\n',num2str(a)));
were num2str(a) would change a, which is defined as a number, into a string of text that could be placed in the title
sin(x-a)
That was my logic behind that... I also suppressed the output with the ";" operator

I thought that this would produce the results I was looking for but the title just gets changed to some kind of number like 14 or 13 or 15 and just stays like that... oddly enough the title I was expecting to get on my graph some how appears in the command window even though I suppressed the output...

I'm hoping someone can explain what I'm doing wrong.

 

[Valkarie]

SolutionThe code you provided should work, but the title command needs to be modified slightly. You can use the sprintf() function to format the string for the title command instead of the fprintf() function. The syntax for the title command should look like this:title(sprintf('sin(x-%s)\n',num2str(a)));The output of the sprintf() function is a string that can be used as the argument to the title command. The output of the fprintf() function is intended for printing text to the console window, not for creating a string to use as an argument.