You know, cosine is adjacent over hypotenuse.

你们知道 cos是邻边除以斜边。

That's the cosine of 30 degrees.

这是cos30度。

98 times the cosine of 30 degrees newtons.

98乘以 cos 30度牛顿。

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

因此 两者等。

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

因此，切片 在这上被压扁的因素正是 theta 的余弦。

Because cosine of 0 right now is 1.

因此 两者等。

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

但让我们再来说说正弦、余弦和对函。

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

还要完成上万笔计算处理余弦，平根，最近还用起了解析几何。

So this is equal to cosine of the angle.

cosθ等于邻边/斜边。

What's the cosine of 30 degrees?

cos30度是多少？

Well, this was T1 of cosine of 30.

这应该对你来说很自然。

And very similarly, this is 60 degrees, so this would be T2 cosine of 60.

非常简单 这是60度现在 关於这两力 我们知道什麽？

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。

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。

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

随着 t 值的增加，该余弦函的内部增加得更慢。

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，我们取两之间的角度或 θ 的余弦。

How is knowing cosines gonna help you with your backstroke?

学会余弦对仰泳有什么帮助？

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）除以它的（振幅）。

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思。