Solving Nonlinear Equations with MATLAB

To use the fsolve function of Matlab, you must first write an M file to describe the nonlinear equations, such

Function eq = nxxf (X)

Global number;

Number = Number + 1

Eq (1) = x (1) * normcf (X (3), 80120231)-0.02 * normcf (x (4), 595042771.7) * exp;

Eq (2) = (log (x (1)/80120231) + 0.02 + 0.5 * (X (2) ^ 2)/X (2)-X (3 );

Eq (3) = x (3)-X (2)-X (4 );

Eq (4) = (normcf (X (3), 595042771.7) * x (1) * X (2)/0.0475;

In this example, each equation is a sub-equation of the other side after the first side is 0. Then, in the MATLAB command window, enter global number; number = 0; y = fsolve ('nxxf', [,]) number. The first parameter of the fsolve function is the function of the nonlinear equations, the second is the initial point, which outputs the result and number of iteration steps.