Adding input parameters to a function

So I have a function that uses fsolve to solve for two variables, lmb_1 and lmb_2. There are two other variables that I'd like to plug into the function. something like root2d(x, phi_0,k) so that I don't have to keep changing the phi_0 and k values in the root2d function.

function F = root2d(x)
phi_0=0.2;
k=0.1;
lmb_1=x(1);
lmb_2=x(2);
s_i = x(1);
s_ii = x(2);
expression_i = phi_0*(k - s_i) + k^2/2 - s_i^2/2 - lmb_1*lmb_2*(log(k) - log(s_i));
expression_ii = phi_0*s_ii - phi_0 - s_ii^2/2 + lmb_1*lmb_2*log(s_ii) + 1/2;
F(1) = expression_i-expression_ii;
F(2) = x(1)-x(2)+phi_0;
end

   x0 = [1,1];
  answer = fsolve(@root2d,x0)

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[Noor Ahmad]

So I attempted this but, when I call the function:

        answer=Lambda1and2Solver_n_1(0.2,0.2,[1 1])

I get a exceeds matrix error.

function F = Lambda1and2Solver_n_1(phi_0,k,x0)
 F = fzero(@Solver,x0);

      function F = Solver(x)
  phi_0=0.2;
  k=0.1;
  lmb_1=x(1);
  lmb_2=x(2);
  s_i = x(1);
  s_ii = x(2);
  expression_i = phi_0*(k - s_i) + k^2/2 - s_i^2/2 - lmb_1*lmb_2*(log(k) - log(s_i));
  expression_ii = phi_0*s_ii - phi_0 - s_ii^2/2 + lmb_1*lmb_2*log(s_ii) + 1/2;
  F(1) = expression_i-expression_ii;
  F(2) = x(1)-x(2)+phi_0;
      end
  end

[Walter Roberson]

   phi_0 = 0.2;
   k = 0.1;
   x0 = [1 1];
   F = fzero(@(x) Lambda1and2Solver_n_1(x, phi_0, k), x0);

function F = Lambda1and2Solver_n_1(x, phi_0, k)
  lmb_1=x(1);
  lmb_2=x(2);
  s_i = x(1);
  s_ii = x(2);
  expression_i = phi_0*(k - s_i) + k^2/2 - s_i^2/2 - lmb_1*lmb_2*(log(k) - log(s_i));
  expression_ii = phi_0*s_ii - phi_0 - s_ii^2/2 + lmb_1*lmb_2*log(s_ii) + 1/2;
  F(1) = expression_i-expression_ii;
  F(2) = x(1)-x(2)+phi_0;
end