>> %复化梯形公式 syms x f(x); =1 / ((sin(x))^2 + 0.25 * (cos(x))^2); a = 0; b = pi / 2; n = 1; h = (b - a) / n; T = h / 2 * (f(a) + f(b)); while true n = n * 2; h = (b - a) / n; T_new = T / 2; for i = 1:n-1 xi = a + i * h; T_new = T_new + h * vpa(f(xi)); end T_new = T_new + h / 2 * (vpa(f(a)) + vpa(f(b))); if abs(T_new - T) < 1e-7 break end T = T_new; end fprintf('复化梯形公式得到的积分值为：%.10f', T);'=' 运算符的使用不正确。 '=' 用于为变量赋值，'==' 用于比较值的相等性。怎么修改

将第一行的等于号改为定义符号变量的语句，即：`syms x f(x)`。最后一行的单引号也需要删除。修改后的代码如下：

syms x f(x);
f(x) = 1 / ((sin(x))^2 + 0.25 * (cos(x))^2);
a = 0;
b = pi / 2;
n = 1;
h = (b - a) / n;
T = h / 2 * (f(a) + f(b));
while true
    n = n * 2;
    h = (b - a) / n;
    T_new = T / 2;
    for i = 1:n-1
        xi = a + i * h;
        T_new = T_new + h * vpa(f(xi));
    end
    T_new = T_new + h / 2 * (vpa(f(a)) + vpa(f(b)));
    if abs(T_new - T) < 1e-7
        break
    end
    T = T_new;
end
fprintf('复化梯形公式得到的积分值为：%.10f', T);