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.

两同时乘重力的大小。

Theta is, how might you proceed?

，您会如何进行？

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

两同时乘重力的大小。

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。

And they observed an increase in so-called theta activity.

他到所谓的 theta 活动有所增加。

I'm gonna use sine of theta, oh sorry, sine of phi.

我要使用正弦 theta， 哦抱歉，正弦 phi。

And now for the Y direction we can use the definition of sine of theta.

现在对于 Y 方向，我使用正弦函数的定义。

So, the cosine of theta is equal to the (ball’s position) divided by its (amplitude).

因此， theta 的余弦等于（球的位置）除它的（振幅）。

" d" theta, which I like to think of as signaling the fact that some kind of limit is being taken.

“d”theta，我喜欢将其视为表明 正在采取某种限制的事实。

But for rotational motion, we really want to know the object’s angle -- what we call theta.

但是对于旋转运动， 我真的想知道物体的角度——我称之为 theta。

You'll remember that we typically designate an angle in a system as theta.

你会记得我通常指的角落 在带有θ字母的系统中。

The angle between the force of gravity and the component pointing into the ramp is called theta.

重力与元素之间的角度 斜率内的向量称为 theta。

And finally, there’s the angle, theta, between the magnetic field and a line perpendicular to the face of the loop.

最后，还有磁场和垂直于环面的线之间的角度θ。

Next, the angle, theta, is just equal to the angular velocity multiplied by time.

接下来，角度θ正好等于 角速度乘时间。

Or, if this is theta, this angle right over here is going to be 90 minus theta.

那么这个角就是90-θ另外一个几何知识 不知道你记不记得。