Fit
 Usage
• Fit[data, funs, vars] 找一个数据列的最小二乘拟合，这个拟合是作为一个以 vars为自变量的函数funs的线性组合。
• 数据有形式    ,  , ... ,   ,   ,  , ... ,   , ...  , 其中坐标数 x, y, ... 等于在列表 vars中的变量数。 • 数据可以有形式   ,  , ...  , 有一个坐标假设是取值 1, 2, ... . • 参数 funs可以是任何仅依赖于对象vars的函数列表。
Notes
• Fit 总是求在列表中的函数的线性组合，使得最小化由值  得出的平方和。 • 作为Fit的输入给出的精确数被转化为有机器精度的近似数。
 Further Examples
You will have to evaluate all the cells in this example to regenerate the data used for the plots. Here is a table of the first 20 primes.
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Here is a plot of this data. Evaluate the cell to see the graphic.
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This gives a quadratic fit to the data.
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Here is a plot of the quadratic fit. Evaluate the cell to see the graphic.
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This shows the quadratic fit superimposed on the original data. The quadratic fit is better than the linear one. Evaluate the cell to see the graphic.
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This gives a table of the values of an exponential function for x from 1 to 10 in steps of 1.
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This fit recovers the original functional form.
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If you include other functions in the list, Fit determines that they occur with small coefficients.
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You can use Chop to get rid of the terms with small coefficients.
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序列进行二次拟合。
