matlab代码求助！

也不是报错吧，就是提示方程在初始点处解出。但是手算的话得出的并不是这个结果。
【Equation solved at initial point.
fsolve completed because the vector of function values at the initial point
is near zero as measured by the default value of the function tolerance, and
the problem appears regular as measured by the gradient.
<stopping criteria details>】

顶

clear all; clc;
syms omega;
% 梁参数
E = 3.45 * 10^3; % 弹性模量 (Pa)
I = 289.81; % 截面惯性矩 (m^4)
rho = 2500; % 梁材料密度 (kg/m^3)
A = 34.36; % 梁的截面积 (m^2)
L = 80; % 每跨长度 (m)
k = 2.96 * 10^9; % 弹簧支座刚度 (N/m)
n = 2; % 跨数
% 流体参数
Cm = 1.2; % 质量系数
rho_w = 1000; % 水的密度 (kg/m^3)
% 等效质量
m = rho * A; % 梁的单位长度质量
m_eff = m + (Cm - 1) * rho_w * A;
% 定义 alpha 作为 omega 的函数
alpha = (omega^2 * m_eff / (E * I))^(1/4);
% 定义符号矩阵A及分块矩阵
A_matrix = sym(zeros(4 * n, 4 * n)); % 确保A_matrix是符号矩阵
A1 = [0, 1, 0, 1;
0, -1, 0, 1];
A2 = [sin(alpha * L), cos(alpha * L), sinh(alpha * L), cosh(alpha * L);
cos(alpha * L), -sin(alpha * L), cosh(alpha * L), sinh(alpha * L);
-sin(alpha * L), -cos(alpha * L), sinh(alpha * L), cosh(alpha * L);
-cos(alpha * L) -(k / (alpha^3 * E * I)) * sin(alpha * L), sin(alpha * L) - (k / (alpha^3 * E * I)) * cos(alpha * L), cosh(alpha * L) - (k / (alpha^3 * E * I)) * sinh(alpha * L), sinh(alpha * L) - (k / (alpha^3 * E * I)) * cosh(alpha * L)];
A3 = [0, -1, 0, -1;
-1, 0, -1, 0;
0, -1, 0, 1;
1, 0, -1, 0];
A4 = [sin(alpha * L), cos(alpha * L), sinh(alpha * L), cosh(alpha * L);
-sin(alpha * L), -cos(alpha * L), sinh(alpha * L), cosh(alpha * L)];
% 构建A_matrix
for i = 1:n-1
% 更新A_matrix的分块
A_matrix(1:2, 1:4) = A1;
A_matrix(4*i-1:4*i+2, 4*i-3:4*i) = A2;
A_matrix(4*i+1:4*i+4, 4*i-3:4*i) = A3;
A_matrix(4*n-1:4*n, 4*n-3:4*n) = A4;
end
% 定义行列式的函数，使用subs将符号矩阵A_matrix的omega替换为数值omega_val
determinant_function = @(omega_val) double(det(subs(A_matrix, omega, omega_val)));
% 定义初始猜测值
omega_initial_guesses = 0.00001;
% 设置 fsolve 的精度选项
options = optimset('TolFun', 1e-8, 'TolX', 1e-8, 'MaxIter', 500, 'MaxFunEvals', 500);
% 求解
omega_solution = fsolve(determinant_function, omega_initial_guesses, options);