Math.Cos&安培; Math.Sin在C＃ [英] Math.Cos & Math.Sin in C#

问题描述

我想的东西，我认为应该是相当简单的。我有一个角度，位置和距离，我想找到X，从这些信息中Y坐标。

I'm trying something that I thought should be reasonably simple. I have an angle, a position and a distance and I want to find the X,Y co-ordinates from this information.

随着90度的例子输入I转换值以弧度用下面的代码：

With an example input of 90 degrees I convert the value to radians with the following code:

public double DegreeToRadian(float angle)
{
  return Math.PI * angle / 180.0;
}

这给了我1.5707963267949弧度
后来，当我使用

This gives me 1.5707963267949 radians Then when I use

Math.Cos(radians)

我最终的一个答案是：6.12303176911189E-17

I end up with an an answer of: 6.12303176911189E-17

到底是什么回事？ 90度的余弦值应为0，所以为什么我收到这样的越轨行为......更重要的是我怎么能阻止它？

What the heck is going on? The cosine of 90 degrees should be 0, so why am I getting such a deviance... and more importantly how can I stop it?

推荐答案

让我来回答与另外一个你的问题：有多远，你认为6.12303176911189E-17为0？你叫什么的偏差的居然是由于浮点数在内部存储的方式。我建议你​​阅读下面的文章。在.NET中，他们使用的是 IEEE 754标准储存。

Let me answer your question with another one: How far do you think 6.12303176911189E-17 is from 0? What you call deviance is actually due to the way floating point numbers are internally stored. I would recommend you reading the following article. In .NET they are stored using the IEEE 754 standard.

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