Fourier introduced the concept of representing functions as sums of sines and cosines.

傅里叶引入了将函数表示为正弦和余弦之和的概念。

With a bit more effort, techies could also compute ratios, inverses , sines, cosines and tangents.

如果再多花点功夫, 这些科技高手还能算出比例 、 数 、 弦、弦和正切等值.