他在数学书的部门找到一些三角学的书？

He found books on trigonometry in the mathematics section.

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大学上微积分课时我做了许多三角学的作业，作业中这个数经常出现。

I had been doing a lot of trig homework for a calculus class I was taking in undergrad and this number appears a lot.

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课题包含利用流体物理学规律，以及物理学和三角学的应用来对血溅形态进行分析。

Topics include the physical laws of fluids and the application of physics and trigonometry to bloodstain pattern analysis.

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