98 times the cosine of 30 degrees newtons.

98乘以 cos 30度牛顿。

So this is equal to cosine of the angle.

cosθ等于邻/斜。

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

但让我们再来说说正弦、余弦和。

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

因此 两者相等。

Because cosine of 0 right now is 1.

因此 两者相等。

What's the cosine of 30 degrees?

cos30度是多？

You know, cosine is adjacent over hypotenuse.

你们知道 cos是邻除以斜。

How is knowing cosines gonna help you with your backstroke?

学会余弦仰泳有什么帮助？

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理任意角度的延伸。

That's the cosine of 30 degrees.

这是cos30度。

So we know that T1 cosine of 30 is going to equal T2 cosine of 60.

所以我们知道T1cos30°应该等於T2cos60°我们把这写下来。

So, for example, I don't think that being a math person means that you can recite the formulas between the sines, cosines, tangents and to use logarithms and exponentials interchangeably.

所以，比如，我认为成为学家不是指你要能背诵正弦、余弦、正切的公式和转化运用和指。

I studied trigonometry for a month. I sometimes dreamed about sine, cosine and tangent, about mysterious angles and concussed computations, but for all this I made no real progress. I could not self-teach trigonometry. But I knew someone who had.

我学习了一个月的三角学。我有时会梦见正弦、余弦和正切，梦见神秘的角度和让我绞尽脑汁的计算，尽管如此，我并未取得任何实质性进展。我无法自学三角学，但我认识一个自学成功的人。