partial diff with out syms plot

theta=1:10;

a=1:10;

N=cos(theta);

pl plot df/dna vs a also plot df/dN vs a

function y=f(N,na,nf,a,b)

nf=2;

y=exp(i*na*N)+sin(nf^2-a)+atan(exp(1*b));

end