单词：spline approximation
样条逼近;样条函数近似
spline approximation的用法和样例：
例句
- While for the sinusoidal approximation method, a detail derivation of the amplitude of each sinusoidal function is re-derived for completeness.为完整性，文中亦详细推导正弦函数近似法中各个频率之振幅。