This right here is 90 minus theta.

那么上面这个角是多少。

So this is 90 minus theta degrees.

这个也是90-θ度。

This is equal to the sine of theta.

两侧可以同时乘以重力的大小。

Theta is, how might you proceed?

，您会如何进行？

So this is going to be equal to the sine of theta.

两侧可以同时乘以重力的大小。

This too will be 90 minus theta degrees.

再看如何求出这个角。

A change from alpha wave drowsiness to lower frequency theta brain waves signify early sleep.

从α波睡意到较低频率的脑电波的变化表示早睡。

So the factor by which the slice gets squished down in this direction is exactly cosine of theta.

因此，切片 在这个方向上被压扁的因素正是 theta 的余弦。

And that's why it's cosine of theta.

因此 两者相等。

However, let's use E dA cosine theta instead of the dot product.

但是，让我们使用 E dA 余弦西塔来代替点积。