请使用matlab编写代码x1 x2 x3 x4和y1 y2 y3 y4分别为四组代表横纵坐标值的列表请使用B样条拟合由xy组成的散点图且要求经过所有点并将拟合后的曲线求导后画出

以下是使用MATLAB进行B样条拟合并求导后绘制曲线的代码：

% 输入四组代表横纵坐标值的列表 x1 = [1, 2, 3, 4, 5]; y1 = [3, 6, 1, 7, 2]; x2 = [1, 2, 3, 4, 5]; y2 = [2, 5, 1, 8, 3]; x3 = [1, 2, 3, 4, 5]; y3 = [4, 2, 8, 5, 1]; x4 = [1, 2, 3, 4, 5]; y4 = [6, 3, 7, 1, 4];

% 将四组坐标值合并成两个矩阵 x = [x1; x2; x3; x4]; y = [y1; y2; y3; y4];

% 使用B样条拟合曲线 t = 1:numel(x1); ts = linspace(t(1), t(end), 100); xx = spline(t, x, ts); yy = spline(t, y, ts);

% 绘制原始散点图和B样条拟合曲线 figure scatter(x(:), y(:)) hold on plot(xx, yy)

% 求导并绘制导数曲线 dx = diff(xx); dy = diff(yy); slopes = dy ./ dx; slopes(isnan(slopes)) = 0; % 处理斜率为NaN的情况 xmid = (xx(1:end-1) + xx(2:end)) / 2; ymid = (yy(1:end-1) + yy(2:end)) / 2; figure plot(xmid, slopes) hold on plot(xx, yy)