In Wavelet Transform, Mexican Hat is quite useful as a mother wavelet. You can try it on MATLAB as below:

% Set effective support and grid parameters. 
lb = -5; ub = 5; n = 1000; 

% Compute and plot Mexican hat wavelet. 
[y,x] = mexihat(lb,ub,n); 

plot(x,y), title('Mexican hat wavelet')

%Generate polynomial formula from row data by interpolation
p = polyfit(x,y,10); %
f = polyval(p,x);
a = poly2sym(f);
r = roots(p);
plot(f);