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。

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

因此 两。

Because cosine of 0 right now is 1.

因此 两。

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，平方根，最近还用起了解析几何。

You know, cosine is adjacent over hypotenuse.

你们知道 cos是邻边除斜边。

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

非常简单 这是60现在 关於这两个力 我们知道什麽？

98 times the cosine of 30 degrees newtons.

98 cos 30牛顿。

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。

What's the cosine of 30 degrees?

cos30是多少？

That's the cosine of 30 degrees.

这是cos30。

Well, this was T1 of cosine of 30.

这应该对你来说很自然。

So the cosine of 30 degrees is equal to-- This over T1 one is equal to the x component over T1.

所cos30於如果你们两边T1 就得到这个。

And the answer to the equation would have been cosine x, like COS x.

这个方程的答案是余弦x，即COS x。

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

因此， theta 的余弦于（球的位置）除它的（振幅）。

And the cosine of 90 degrees is zero.

90的余弦值是零。

There are others, sine, cosine, add, subtract.

还有其他的，如正弦、余弦、加法、减法。

They use the cosine transform in JPG.

他们在JPG中使用了余弦变换。

How is knowing cosines gonna help you with your backstroke?

会余弦对仰泳有什么帮助？

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

这是三角，上边 及跨正弦和余弦的角。

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。