我们还可以通过解出式中余弦的方法，得到两向量间的角度。

And, we can use that to measure angles between vectors by solving for cosine in this.

youdao

这种方法有节制的信号分解成一系列的波形正弦和余弦的组成部分。

This method decomposes a measured signals waveform into a series of sine and cosine components.

youdao

采用正弦和余弦的泰勒展开式构造的迭代公式，计算一个绘图点只需9次加法。

Adopt the iterative formula that forms Taylor's expansion of sine and cosine, and compute a graphic points are only calculated by 9 times addition.

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Then you're supposed to know derivatives of simple functions like sines and cosines.

你应该知道一些简单函数的导数,比如正弦函数和余弦函数

耶鲁公开课 - 基础物理课程节选

sine and cosine are definite numbers.

正弦和余弦都是有限大小的数

耶鲁公开课 - 基础物理课程节选

I'm using the fact that when you take a cosine and change the angle inside the cosine, it doesn't care. whereas, if you go to the sine and change the angle inside the sine, it becomes minus sine.

我用了一个结论,当你使用余弦函数时,改变角度的正负,函数值不变,而对于正弦函数,改变角度的符号,则函数值也会变号

耶鲁公开课 - 基础物理课程节选