How to write equation with exponential in matlab

function s = newton_ls(y,d)
% initilaize lamba=0
s=0;
% let theta_d and theta_dd be the first and second dreivative of theta
while 1
    theta_d = first_d(s);
    theta_dd = second_d(s);
    diff = - theta_d/theta_dd;
    s= s+diff;
    if abs(diff)<0.01
        break;
    end    
end
    function t_d = first_d(s)
        t_d= 2*d(1,1)+(6*(d(2,1)^2*s))+(6*(d(2,1)*y(2,1))+((2*d(2,1))*((d(2,1)*s)+y(2,1)))+(4*d(1,1))*((d(1,1)*s)+y(1,1)))*exp(((d(2,1)*s)+y(2,1)^2)+((2*d(1,1)*s)+(y(1,1)))^2);
        
    end
    function t_dd = second_d(s)
        t_dd=12*d(2,1)+2*d(2,1)^2+2*d(2,1)*d(2,1)*s+y(2,1)+4*d(1,1)*d(2,1)*s+y(1,1)^2*exp(d(2,1)*s+y(2,1)^2+2*d(1,1)*s+y(1,1)^2+2*d(2,1)^2+4*d(1,1)^2)*exp(d(2,1)*s+y(2,1)^2)+(2*d(1,1)*s+y(1,1)^2);
        
    end
end

I got an error donno how to fix it

[Walter Roberson]

How are you invoking the function, and what error message are you getting?

[Torsten]

How did you call "newton_ls" ? How did you choose y and d ?