In this paper, the formula of partial derivative of second order on compound function of many varables is established.

本文建立了多元复合函数的二阶偏导数公式。

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For all samples, the raw spectra were pretreated as second derivative and Norris derivative filter(7,5). partial least square (PLS) was used as the calibration algorithm.

在所有的校正模型中，原始谱图经过二阶导数和偏最小二乘（ PLS）处理，20个外部样品用于所建模型的验证，实际和预测的平均相对偏差<5%。

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The factor of the mixed partial derivative term controls the grid orthogonality. The other two factors of second order partial derivative terms control the grid spacing.

结果表明 ：方程中混合偏导数项系数具有控制网格正交性的作用；

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So, using those, now, what happens if we take the second derivative of A, the mixed derivative, partial with respect to T and the partial with respect to V.

如果我取A的二阶导数,混合导数，对T偏微分,再对V偏微分。

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