Steepest descent method with newtons method

My objective function is 2𝑥1 + 3𝑥2 ^2 + 𝑒( 2𝑥1 ^2+𝑥2^ 2 )

I have tried this code but nothing worked

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

%nested function to define my first derivative and second derivative of lamba

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(1,2)*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

Kindly help me with suggestions