Matlab - Reconocimiento ecuaciones en GUI

function varargout = der_int_transf_caballero(varargin)

gui_Singleton = 1;

gui_State = struct('gui_Name',       mfilename, ...

                   'gui_Singleton',  gui_Singleton, ...

                   'gui_OpeningFcn', @der_int_transf_caballero_OpeningFcn, ...

                   'gui_OutputFcn',  @der_int_transf_caballero_OutputFcn, ...

                   'gui_LayoutFcn',  [] , ...

                   'gui_Callback',   []);

if nargin && ischar(varargin{1})

    gui_State.gui_Callback = str2func(varargin{1});

end

if nargout

    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});

else

    gui_mainfcn(gui_State, varargin{:});

end

function der_int_transf_caballero_OpeningFcn(hObject, ~, handles, varargin)

handles.output = hObject;

guidata(hObject, handles);

function varargout = der_int_transf_caballero_OutputFcn(~, ~, handles)

varargout{1} = handles.output;

function leer_la_funcion_Callback(hObject, ~, handles)

fun=get(hObject,'String');

handles.fun=fun;

guidata(hObject, handles);

function integral_Callback(hObject, ~, handles)

fun=handles.fun;

int_fun=int(sym(fun));

set(handles.text3,'String',char(int_fun));

guidata(hObject, handles);

function derivar_Callback(hObject, ~, handles)

fun=handles.fun;

der_fun=diff(sym(fun));

set(handles.text4,'String',char(der_fun));

guidata(hObject, handles);

function transformada_Callback(hObject, ~, handles)

fun=handles.fun;

fourier_fun=fourier(sym(fun));

set(handles.text5,'String',char(fourier_fun));

guidata(hObject, handles);