But let me go back to these sines, cosines and logarithms.

但让我们再来说说正弦、余弦和对数函数。

I actually write it with these little ridges in it, so SOH... CAH... TOA.

我写的时候会写成这种三角的形状，这是正弦，余弦，正切。

And compute over 10,000 calculations by cosine, square root and lately Analytic Geometry.

还要完成上万笔计算处余弦，平方根，最近还用起了解析几何。

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

此，切片 在这个方向上被扁的素正是 theta 的余弦。

And the cosine of 90 degrees is zero.

90 度的余弦为零。

The cosine of zero is 1.

零的余弦是 1。

How is knowing cosines gonna help you with your backstroke?

学会余弦对仰泳有什么帮助？

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。

I don't have the slightest idea what sine and cosine mean.

我根本不知道正弦和余弦是什么意。

As the value t increases, the inside of this cosine function increases more slowly.

随着 t 值的增加，该余弦函数的内部增加得更慢。

It's all just trigonometry, connecting sides and angles through sines and cosines.

这是三角学，上边 以及跨正弦和余弦的角度。

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

此， theta 的余弦等于（球的位置）除以它的（振幅）。

So, the law of cosines is an extension of the pythagorean theorem to the arbitrary angles...

所以余弦定律是勾股定对任意角度的延伸。

To calculate a triangle's shading, we take the  cosine of the angle or theta between the two directions.

为了计算三角形的阴影，我们取两个方向之间的角度或 θ 的余弦。

And then I need to multiply by cosine of the angle in this case the angle is 30 degrees.

然后我需要乘以角度的余弦，在这种情况下角度是 30 度。

In other words, the ball’s position is equal to (the amplitude), times (the cosine of the angle).

换句话说， 球的位置等于（振幅）乘以（角度的余弦值）。

Well, it's going to be the tension in the first wire, 200 Newtons times the cosine of 30 degrees.

好吧，这将是第一根电线的张力，200 牛顿乘以 30 度的余弦。

Then the real part of the sum is the cosine amplitude and the imaginary part is the sine amplitude.

那么总和的实部是余弦振幅，虚部是正弦振幅。

The  force of gravity perpendicular equals mass times gravitational field strength times the cosine of  the incline angle.

垂直重力等于质量乘以重力场强度乘以倾斜角的余弦。

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

此，切片在这个方向上被扁的素正是 theta 的余弦。