作业帮matlab 函数定义x=[-3.15,-1.73,-1.46,-1.41,-1.34,-1.25,-1.22];y=[-4,-3,-2,-1,0,1,2];a=polfit(x,y,2);b=polfit(x,y,3);我想用二次和三次多项式拟和原曲线接下来的如何写?画在同一张图中,
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![matlab 函数定义x=[-3.15,-1.73,-1.46,-1.41,-1.34,-1.25,-1.22];y=[-4,-3,-2,-1,0,1,2];a=polfit(x,y,2);b=polfit(x,y,3);我想用二次和三次多项式拟和原曲线接下来的如何写?画在同一张图中,](/uploads/image/z/1340405-53-5.jpg?t=matlab+%E5%87%BD%E6%95%B0%E5%AE%9A%E4%B9%89x%3D%5B-3.15%2C-1.73%2C-1.46%2C-1.41%2C-1.34%2C-1.25%2C-1.22%5D%3By%3D%5B-4%2C-3%2C-2%2C-1%2C0%2C1%2C2%5D%3Ba%3Dpolfit%28x%2Cy%2C2%29%3Bb%3Dpolfit%28x%2Cy%2C3%29%3B%E6%88%91%E6%83%B3%E7%94%A8%E4%BA%8C%E6%AC%A1%E5%92%8C%E4%B8%89%E6%AC%A1%E5%A4%9A%E9%A1%B9%E5%BC%8F%E6%8B%9F%E5%92%8C%E5%8E%9F%E6%9B%B2%E7%BA%BF%E6%8E%A5%E4%B8%8B%E6%9D%A5%E7%9A%84%E5%A6%82%E4%BD%95%E5%86%99%3F%E7%94%BB%E5%9C%A8%E5%90%8C%E4%B8%80%E5%BC%A0%E5%9B%BE%E4%B8%AD%2C)
matlab 函数定义x=[-3.15,-1.73,-1.46,-1.41,-1.34,-1.25,-1.22];y=[-4,-3,-2,-1,0,1,2];a=polfit(x,y,2);b=polfit(x,y,3);我想用二次和三次多项式拟和原曲线接下来的如何写?画在同一张图中,
matlab 函数定义
x=[-3.15,-1.73,-1.46,-1.41,-1.34,-1.25,-1.22];
y=[-4,-3,-2,-1,0,1,2];
a=polfit(x,y,2);
b=polfit(x,y,3);
我想用二次和三次多项式拟和原曲线接下来的如何写?
画在同一张图中,
matlab 函数定义x=[-3.15,-1.73,-1.46,-1.41,-1.34,-1.25,-1.22];y=[-4,-3,-2,-1,0,1,2];a=polfit(x,y,2);b=polfit(x,y,3);我想用二次和三次多项式拟和原曲线接下来的如何写?画在同一张图中,
俺明白你的意思.
把以下文件存为y.m
function f=y(t)
x = (0:.1:2)';
y = [5.8955 3.5639 2.5173 1.9790 1.8990 1.3938 1.1359 1.0096 1.0343 ...
0.8435 0.6856 0.6100 0.5392 0.3946 0.3903 0.5474 0.3459 0.1370 ...
0.2211 0.1704 0.2636]';
pp=spline(x,y);
f=ppval(pp,t);
plot(x,y,'o-');
可以执行验证.
>> y(0)
ans = 5.8955
>> y(0.1)
ans = 3.5639
>> y(1/3) %这个表里可不能直接查询哦!
ans = 1.9479
>> y(9) %还可以外推呢,准不准就不好说了,显然外推太多是不行的.
ans = 3.1030e+004