Input arguments must be 'double'.? Sin, Sawtooth, Square functions.

I have this function

% --- Executes on button press in radiobutton4.
function radiobutton4_Callback(hObject, eventdata, handles)

a=handles.edit5; 

f=handles.edit2;

r1=handles.edit7;

r2=handles.edit8;

c=handles.edit9;

w=2*pi*f; 

syms x

xn=0:0.01:2*f;

y=a*sin((w*x));

Y=int(y,x);

z=(-1/(r1*c)).*Y

yn = subs(y, x, xn);

zn = subs(z, x, xn);

axes(handles.axes2)

plot(xn, yn, xn, zn, 'g');

grid on

static= [num2str(-r2/r1) ' v/v'];

set(handles.text5,'String',static);

static2= [num2str((-1/(r1*c))*a*2*f) 'V'];

set(handles.text9,'String',static2);

And it works correctly but when I replace "sin" with "sawtooth" or "square" like this

% --- Executes on button press in radiobutton4.
function radiobutton4_Callback(hObject, eventdata, handles)

a=handles.edit5; 

f=handles.edit2;

r1=handles.edit7;

r2=handles.edit8;

c=handles.edit9;

w=2*pi*f; 

syms x

xn=0:0.01:2*f;

y=a*sawtooth((w*x));

Y=int(y,x);

z=(-1/(r1*c)).*Y

yn = subs(y, x, xn);

zn = subs(z, x, xn);

axes(handles.axes2)

plot(xn, yn, xn, zn, 'g');

grid on

static= [num2str(-r2/r1) ' v/v'];

set(handles.text5,'String',static);

static2= [num2str((-1/(r1*c))*a*2*f) 'V'];

set(handles.text9,'String',static2);

It gives me this error

Error using proyectoanaloga2>radiobutton4_Callback (line 211)
Input arguments must be 'double'.

Error in gui_mainfcn (line 96)
        feval(varargin{:});

Error in proyectoanaloga2 (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in
@(hObject,eventdata)proyectoanaloga2('radiobutton4_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating uicontrol Callback

In that line:

y=a*sawtooth((w*x));

What can I do? Thank you so much.

Answer 1

[Walter Roberson]

sawtooth() is a numeric routine from the Signal Processing Toolbox. You are attempting to pass a symbolic variable in to it, get out some kind of symbolic sawtooth formula, and then do a symbolic integration on the formula. All of which fails because sawtooth() just is not a symbolic routine.

I do not have a symbolic formula for sawtooth available at the moment. Ah, here is one:

PI = sym('PI');
abs(2*x/PI+1-4*floor((1/2)*x/PI+3/4))-1

using sym('PI') is for accuracy.

Do not expect a closed form solution when you integrate