Matlab 如何用for循环的答案填充零向量？

我创建了一个名为

result = zeros(1,20);

在GNU倍频程GUI上，我想用for循环的积分估计来填充零

a = 0;
b = 3;
f = @(x) sin(10 *x.^2);

for i = 20
    n = 2.^i;
    dx = (b - a) / n;
    left = a:dx: (b - dx);
    right = (a+dx) :dx:b;
    h1 = f(left);
    h2 = f(right);
    areas = (h1 + h2) ./ 2 .* dx;
    totalarea = sum(areas)
endfor

有谁能告诉我如何用上面for循环中的

totalarea

值填充

result

矩阵吗？

请参见注释：

result = zeros(1,20);
a = 0;
b = 3;
f = @(x) sin(10 *x.^2);

for i = 1:20 % make sure you loop from 1 to 20
    n = 2.^i; 
    dx = (b - a) / n;
    left = a:dx: (b - dx);
    right = (a+dx) :dx:b;
    h1 = f(left);
    h2 = f(right);
    areas = (h1 + h2) ./ 2 .* dx;
    totalarea = sum(areas);
    result(i) = totalarea; % put the totalarea in the i'th position in the result matrix
endfor